424 lines
14 KiB
Dart
424 lines
14 KiB
Dart
import 'package:flutter/foundation.dart';
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import 'package:flutter_webrtc/flutter_webrtc.dart';
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import '../config/ice_servers.dart';
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import '../models/signal_message.dart';
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import '../proto/control_message.pb.dart';
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import '../signaling/signaling_client.dart';
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import '../utils/control_commands.dart';
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/// 封装 WebRTC 连接逻辑（对应 Android 端 WebRtcClient）。
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///
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/// 职责：
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/// - 创建 PeerConnection（recvonly 视频 + 控制用 DataChannel）
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/// - 创建 Offer 并通过信令发送
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/// - 处理 Answer / ICE 候选
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/// - 通过 DataChannel 发送控制指令（触摸/滑动/按键）
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/// - 采集并解析连接统计信息
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///
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/// 本类同时兼容 Android 与 iOS（基于 flutter_webrtc）。
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class WebRtcController {
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final SignalingClient signaling;
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final String deviceId;
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final String targetDeviceId;
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final String? authType;
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final String? authValue;
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RTCPeerConnection? _pc;
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RTCDataChannel? _dataChannel;
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/// 远端视频渲染器，由调用方持有并显示。
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final RTCVideoRenderer renderer = RTCVideoRenderer();
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void Function()? onConnectionEstablished;
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void Function(String error)? onConnectionFailed;
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void Function()? onDisconnected;
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/// ICE 连接断开（如网络中断、被控端退出），用于提示用户并返回连接设置。
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void Function(String message)? onIceDisconnected;
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/// 远端视频流就绪（renderer 已绑定视频轨道）。
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void Function(RTCVideoRenderer renderer)? onRemoteStream;
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WebRtcController({
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required this.signaling,
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required this.deviceId,
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required this.targetDeviceId,
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this.authType,
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this.authValue,
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});
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/// 初始化渲染器、PeerConnection，并创建 Offer。
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Future<void> initialize() async {
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await renderer.initialize();
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final configuration = {
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'iceServers': kIceServers,
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'sdpSemantics': 'unified-plan',
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'iceCandidatePoolSize': 10,
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// 增强复杂网络下的稳定性，参考 Android 端配置。
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'continualGatheringPolicy': 'gatherContinually',
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'iceTransportsType': 'all',
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'tcpCandidatePolicy': 'enabled',
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};
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_pc = await createPeerConnection(configuration);
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_pc!.onIceCandidate = _onIceCandidate;
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_pc!.onIceConnectionState = _onIceConnectionState;
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_pc!.onTrack = _onTrack;
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_pc!.onDataChannel = _onDataChannel;
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// 仅接收远端视频（recvonly）。
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await _pc!.addTransceiver(
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kind: RTCRtpMediaType.RTCRtpMediaTypeVideo,
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init: RTCRtpTransceiverInit(direction: TransceiverDirection.RecvOnly),
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);
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// 创建控制用 DataChannel。
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// 使用非可靠、无序模式以降低延迟，解决“不跟手”问题。
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final dcInit = RTCDataChannelInit()
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..ordered = false
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..maxRetransmits = 0;
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_dataChannel = await _pc!.createDataChannel(kDataChannelLabel, dcInit);
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_setupDataChannel(_dataChannel!);
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// 创建并发送 Offer。
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final constraints = {
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'mandatory': {
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'OfferToReceiveVideo': true,
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'OfferToReceiveAudio': false,
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},
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'optional': [],
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};
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final offer = await _pc!.createOffer(constraints);
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await _pc!.setLocalDescription(offer);
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_sendOffer(offer.sdp!, authType: authType, authValue: authValue);
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}
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void _onTrack(RTCTrackEvent event) {
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if (event.track.kind == 'video' && event.streams.isNotEmpty) {
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renderer.srcObject = event.streams[0];
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onRemoteStream?.call(renderer);
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}
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}
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void _onDataChannel(RTCDataChannel channel) {
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// 被控端也可能主动创建 DataChannel，统一处理。
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_setupDataChannel(channel);
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}
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void _setupDataChannel(RTCDataChannel channel) {
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channel.onMessage = (RTCDataChannelMessage message) {
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// 处理来自被控端的消息（本控制端主要发送，此处仅做日志记录）。
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if (message.isBinary) {
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try {
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final command = ControlMessage.fromBuffer(message.binary);
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// ignore: avoid_print
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print('DataChannel message: ${command.action}');
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} catch (e) {
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// ignore: avoid_print
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print('DataChannel message decode failed: $e');
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}
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} else {
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// ignore: avoid_print
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print('DataChannel text message: ${message.text}');
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}
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};
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channel.onDataChannelState = (RTCDataChannelState state) {
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// ignore: avoid_print
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print('DataChannel state: $state');
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};
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}
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void _onIceCandidate(RTCIceCandidate candidate) {
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final payload = {
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'sdpMid': candidate.sdpMid,
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'sdpMLineIndex': candidate.sdpMLineIndex,
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'candidate': candidate.candidate,
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};
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final msg = SignalMessage.withPayload(
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type: 'ICE_CANDIDATE',
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fromDeviceId: deviceId,
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toDeviceId: targetDeviceId,
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deviceType: 'CONTROLLER',
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payload: payload,
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);
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signaling.send(msg);
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}
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void _onIceConnectionState(RTCIceConnectionState state) {
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// ignore: avoid_print
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print('ICE connection state: $state');
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if (state == RTCIceConnectionState.RTCIceConnectionStateConnected) {
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_connectedAt = DateTime.now().millisecondsSinceEpoch;
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onConnectionEstablished?.call();
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} else if (state == RTCIceConnectionState.RTCIceConnectionStateDisconnected) {
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onIceDisconnected?.call('ICE 连接已断开');
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} else if (state == RTCIceConnectionState.RTCIceConnectionStateFailed) {
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onConnectionFailed?.call('ICE 连接失败');
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onDisconnected?.call();
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}
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}
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void _sendOffer(String sdp, {String? authType, String? authValue}) {
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final payload = {'sdp': sdp};
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final msg = SignalMessage.withPayload(
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type: 'OFFER',
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fromDeviceId: deviceId,
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toDeviceId: targetDeviceId,
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deviceType: 'CONTROLLER',
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payload: payload,
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authType: authType,
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authValue: authValue,
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);
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signaling.send(msg);
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}
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/// 处理来自信令服务器的 Answer。
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Future<void> handleAnswer(String sdp) async {
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final answer = RTCSessionDescription(sdp, 'answer');
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await _pc?.setRemoteDescription(answer);
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}
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/// 处理来自信令服务器的 ICE 候选。
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Future<void> handleIceCandidate(Map<String, dynamic> payload) async {
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final candidate = RTCIceCandidate(
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payload['candidate'] as String,
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payload['sdpMid'] as String?,
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payload['sdpMLineIndex'] as int?,
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);
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await _pc?.addCandidate(candidate);
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}
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/// 通过 DataChannel 发送控制指令（protobuf 二进制）。
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void sendControlCommand(ControlMessage command) {
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if (_dataChannel?.state == RTCDataChannelState.RTCDataChannelOpen) {
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debugPrint('WebRtcController: Sending command -> ${command.action}');
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_dataChannel!.send(RTCDataChannelMessage.fromBinary(command.writeToBuffer()));
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}
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}
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/// 请求被控端切换屏幕采集分辨率（SET_RESOLUTION 指令）。
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void sendResolutionChange(int width, int height, int fps) {
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sendControlCommand(ControlCommands.setResolution(width, height, fps));
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}
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/// 上一次统计采样的字节数与时间戳，用于计算每秒网速。
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int _prevBytesReceived = 0;
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int _prevBytesSent = 0;
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int _prevStatsTimestamp = 0;
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/// 连接建立时的时间戳（毫秒），用于计算连接时长。
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int? _connectedAt;
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/// 采集连接统计信息，回调格式化后的文本（对应 Android 端 updateStats）。
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///
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/// 包含：分辨率/帧率/延迟/解码格式、抖动、丢包率、丢帧、
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/// 每秒上下行网速、连接类型(P2P/TURN)+候选协议、连接时长、
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/// 控制 DataChannel 状态与收发消息数。
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Future<String> getStatsText() async {
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if (_pc == null) return '';
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final reports = await _pc!.getStats();
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dynamic width = '-';
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dynamic height = '-';
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dynamic fps = '-';
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dynamic delay = '-';
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dynamic codec = '-';
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dynamic jitter = '-';
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dynamic lossRate = '-';
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dynamic framesDropped = '-';
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int bytesReceived = 0;
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int bytesSent = 0;
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String? localCandidateId;
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String? remoteCandidateId;
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bool hasNominatedPair = false;
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// 控制 DataChannel 统计（仅统计与对端的控制通道）。
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int dcMessagesSent = 0;
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int dcMessagesReceived = 0;
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for (final report in reports) {
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final values = report.values;
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final type = report.type;
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if (type == 'inbound-rtp' && values['kind'] == 'video') {
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width = values['frameWidth'] ?? '-';
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height = values['frameHeight'] ?? '-';
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fps = values['framesPerSecond'] ?? '-';
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final j = values['jitter'];
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if (j is num) jitter = (j * 1000).toStringAsFixed(0);
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final pr = values['packetsReceived'];
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final pl = values['packetsLost'];
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if (pr is num && pl is num) {
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final total = pr + pl;
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lossRate = total > 0 ? ((pl / total) * 100).toStringAsFixed(1) : '0.0';
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}
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final fd = values['framesDropped'];
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if (fd is num) framesDropped = fd;
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final codecId = values['codecId'];
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if (codecId != null) {
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final codecReport = reports.where((r) => r.id == codecId).firstOrNull;
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final mime = codecReport?.values['mimeType'];
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if (mime is String && mime.startsWith('video/')) {
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codec = mime.substring(6);
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}
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}
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} else if (type == 'candidate-pair') {
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if (values['nominated'] == true) {
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hasNominatedPair = true;
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final rtt = values['currentRoundTripTime'];
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if (rtt is num) {
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delay = (rtt * 1000).toStringAsFixed(0);
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}
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// candidate-pair 的 bytesReceived/bytesSent 为整条连接（视频+DataChannel+ICE）的累计值。
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final br = values['bytesReceived'];
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final bs = values['bytesSent'];
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if (br is num) bytesReceived = br.toInt();
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if (bs is num) bytesSent = bs.toInt();
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final lc = values['localCandidateId'];
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final rc = values['remoteCandidateId'];
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if (lc is String) localCandidateId = lc;
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if (rc is String) remoteCandidateId = rc;
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}
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} else if (type == 'data-channel') {
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if (values['label'] == kDataChannelLabel) {
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final ms = values['messagesSent'];
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final mr = values['messagesReceived'];
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if (ms is num) dcMessagesSent = ms.toInt();
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if (mr is num) dcMessagesReceived = mr.toInt();
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}
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}
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}
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// 计算每秒网速（与上次采样差值）。
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final now = DateTime.now().millisecondsSinceEpoch;
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String downSpeed = '-';
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String upSpeed = '-';
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if (_prevStatsTimestamp != 0) {
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final dt = (now - _prevStatsTimestamp) / 1000.0;
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if (dt > 0) {
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final downBps = (bytesReceived - _prevBytesReceived) / dt;
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final upBps = (bytesSent - _prevBytesSent) / dt;
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downSpeed = _formatSpeed(downBps);
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upSpeed = _formatSpeed(upBps);
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}
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}
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_prevBytesReceived = bytesReceived;
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_prevBytesSent = bytesSent;
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_prevStatsTimestamp = now;
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// 连接类型（P2P/TURN）与候选协议（udp/tcp）。
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String connType = '-';
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String protocol = '-';
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if (hasNominatedPair) {
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connType =
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_resolveConnectionType(reports, localCandidateId, remoteCandidateId);
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protocol = _resolveProtocol(reports, localCandidateId, remoteCandidateId);
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}
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// 连接时长。
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String duration = '-';
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if (_connectedAt != null) {
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final secs = ((now - _connectedAt!) / 1000).floor();
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final m = (secs ~/ 60).toString().padLeft(2, '0');
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final s = (secs % 60).toString().padLeft(2, '0');
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duration = '$m:$s';
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}
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// 控制 DataChannel 状态。
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final dcState = _dataChannel?.state;
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final dcStatus = dcState == RTCDataChannelState.RTCDataChannelOpen
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? '已连接'
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: (dcState == null ? '未连接' : dcState.name);
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return '分辨率: ${width}x$height 帧率: $fps 延迟: $delay ms\n'
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'解码格式: $codec 抖动: $jitter ms 丢包: $lossRate%\n'
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'丢帧: $framesDropped ↓下载: $downSpeed ↑上传: $upSpeed\n'
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'连接类型: $connType ($protocol) 时长: $duration\n'
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'控制通道: $dcStatus 收发: $dcMessagesSent/$dcMessagesReceived';
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}
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/// 依据选定候选对的本地/远端候选类型，返回 P2P / TURN 中继描述。
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String _resolveConnectionType(
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List<StatsReport> reports,
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String? localCandidateId,
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String? remoteCandidateId,
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) {
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String? typeOf(String? id) {
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if (id == null) return null;
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final report = reports.where((r) => r.id == id).firstOrNull;
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final t = report?.values['candidateType'];
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return t is String ? t : null;
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}
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final local = typeOf(localCandidateId);
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final remote = typeOf(remoteCandidateId);
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final isRelay = local == 'relay' || remote == 'relay';
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if (isRelay) {
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// 进一步用本地候选具体类型细化（优先说明本端是否经 TURN 中继）。
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if (local == 'relay') return 'TURN 中继 (本端经服务器)';
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return 'TURN 中继';
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}
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// host: 同一局域网直连; srflx/prflx: 经 NAT 打洞的 P2P。
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return 'P2P 直连';
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}
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/// 返回选定候选对的传输协议（udp/tcp）。
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String _resolveProtocol(
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List<StatsReport> reports,
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String? localCandidateId,
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String? remoteCandidateId,
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) {
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String protoOf(String? id) {
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if (id == null) return '-';
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final report = reports.where((r) => r.id == id).firstOrNull;
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final p = report?.values['protocol'];
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return p is String ? p : '-';
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}
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final local = protoOf(localCandidateId);
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final remote = protoOf(remoteCandidateId);
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if (local != '-' && remote != '-' && local != remote) {
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return '$local/$remote';
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}
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return local != '-' ? local : remote;
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}
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/// 将字节/秒格式化为人类可读字符串（B/s、KB/s、MB/s）。
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String _formatSpeed(double bytesPerSecond) {
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if (bytesPerSecond >= 1024 * 1024) {
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return '${(bytesPerSecond / (1024 * 1024)).toStringAsFixed(1)} MB/s';
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} else if (bytesPerSecond >= 1024) {
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return '${(bytesPerSecond / 1024).toStringAsFixed(1)} KB/s';
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}
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return '${bytesPerSecond.toStringAsFixed(0)} B/s';
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}
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/// 释放所有资源。
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Future<void> close() async {
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try {
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await _dataChannel?.close();
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} catch (_) {}
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try {
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await _pc?.close();
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} catch (_) {}
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try {
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await renderer.dispose();
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} catch (_) {}
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_dataChannel = null;
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_pc = null;
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// 重置网速统计基线，避免下次连接首帧显示错误的瞬时速率。
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_prevBytesReceived = 0;
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_prevBytesSent = 0;
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_prevStatsTimestamp = 0;
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_connectedAt = null;
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}
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}
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