feat: Stats monitor for Track. (#290)

* feat: Stats monitor for Track.

* fix analyze.

* fix.

* import sorter.

* add monitor layer for example.

* update.

* update.

* fix import sorter.

* update.

* import sorter.

* fix typo for filename.

* revert changes for VideoPublishOptions.videoCodec.

* chore: improve code.

* update.

lib/src/events.dart

@@ -7,6 +7,7 @@ import 'participant/remote.dart';
 import 'publication/local.dart';
 import 'publication/remote.dart';
 import 'publication/track_publication.dart';
+import 'track/stats.dart';
 import 'track/track.dart';
 import 'types/other.dart';
 import 'types/participant_permissions.dart';
@@ -435,3 +436,57 @@ class AudioPlaybackStatusChanged with RoomEvent {
   String toString() => '${runtimeType}'
       'Audio Playback Status Changed, isPlaying: ${isPlaying})';
 }
+
+class AudioSenderStatsEvent with TrackEvent {
+  final AudioSenderStats stats;
+  final num currentBitrate;
+  const AudioSenderStatsEvent({
+    required this.stats,
+    required this.currentBitrate,
+  });
+
+  @override
+  String toString() => '${runtimeType}'
+      'stats: ${stats})';
+}
+
+class VideoSenderStatsEvent with TrackEvent {
+  final Map<String, VideoSenderStats> stats;
+  final Map<String, num> bitrateForLayers;
+  final num currentBitrate;
+  const VideoSenderStatsEvent({
+    required this.stats,
+    required this.currentBitrate,
+    required this.bitrateForLayers,
+  });
+
+  @override
+  String toString() => '${runtimeType}'
+      'stats: ${stats})';
+}
+
+class AudioReceiverStatsEvent with TrackEvent {
+  final AudioReceiverStats stats;
+  final num currentBitrate;
+  const AudioReceiverStatsEvent({
+    required this.stats,
+    required this.currentBitrate,
+  });
+
+  @override
+  String toString() => '${runtimeType}'
+      'stats: ${stats})';
+}
+
+class VideoReceiverStatsEvent with TrackEvent {
+  final VideoReceiverStats stats;
+  final num currentBitrate;
+  const VideoReceiverStatsEvent({
+    required this.stats,
+    required this.currentBitrate,
+  });
+
+  @override
+  String toString() => '${runtimeType}'
+      'stats: ${stats})';
+}

lib/src/track/local/audio.dart

@@ -1,12 +1,15 @@
 import 'dart:async';
 
+import 'package:collection/collection.dart';
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
 import 'package:meta/meta.dart';
 
+import '../../events.dart';
 import '../../proto/livekit_models.pb.dart' as lk_models;
 import '../../types/other.dart';
 import '../audio_management.dart';
 import '../options.dart';
+import '../stats.dart';
 import 'local.dart';
 
 class LocalAudioTrack extends LocalTrack
@@ -25,6 +28,58 @@ class LocalAudioTrack extends LocalTrack
     }
   }
 
+  num? _currentBitrate;
+  get currentBitrate => _currentBitrate;
+  AudioSenderStats? prevStats;
+
+  @override
+  Future<void> monitorSender() async {
+    if (sender == null) {
+      _currentBitrate = 0;
+      return;
+    }
+    final stats = await getSenderStats();
+
+    if (stats != null && prevStats != null && sender != null) {
+      _currentBitrate = computeBitrateForSenderStats(stats, prevStats);
+      events.emit(
+          AudioSenderStatsEvent(stats: stats, currentBitrate: currentBitrate));
+    }
+
+    prevStats = stats;
+  }
+
+  Future<AudioSenderStats?> getSenderStats() async {
+    if (sender == null) {
+      return null;
+    }
+
+    final stats = await sender!.getStats();
+    AudioSenderStats? senderStats;
+    for (var v in stats) {
+      if (v.type == 'outbound-rtp') {
+        senderStats ??= AudioSenderStats(v.id, v.timestamp);
+        senderStats.packetsSent = getNumValFromReport(v.values, 'packetsSent');
+        senderStats.packetsLost = getNumValFromReport(v.values, 'packetsLost');
+        senderStats.bytesSent = getNumValFromReport(v.values, 'bytesSent');
+        senderStats.roundTripTime =
+            getNumValFromReport(v.values, 'roundTripTime');
+        senderStats.jitter = getNumValFromReport(v.values, 'jitter');
+
+        final c = stats.firstWhereOrNull((element) => element.type == 'codec');
+        if (c != null) {
+          senderStats.mimeType = getStringValFromReport(c.values, 'mimeType');
+          senderStats.payloadType =
+              getNumValFromReport(c.values, 'payloadType');
+          senderStats.channels = getNumValFromReport(c.values, 'channels');
+          senderStats.clockRate = getNumValFromReport(c.values, 'clockRate');
+        }
+        break;
+      }
+    }
+    return senderStats;
+  }
+
   // private constructor
   @internal
   LocalAudioTrack(
@@ -45,7 +100,7 @@ class LocalAudioTrack extends LocalTrack
   static Future<LocalAudioTrack> create([
     AudioCaptureOptions? options,
   ]) async {
-    options ??= const AudioCaptureOptions();
+    options = const AudioCaptureOptions();
     final stream = await LocalTrack.createStream(options);
 
     return LocalAudioTrack(

lib/src/track/local/local.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
@@ -15,6 +17,7 @@ import '../../types/other.dart';
 import '../options.dart';
 import '../remote/audio.dart';
 import '../remote/video.dart';
+import '../stats.dart';
 import '../track.dart';
 import 'audio.dart';
 import 'video.dart';
@@ -195,7 +198,7 @@ abstract class LocalTrack extends Track {
     }
 
     logger.fine('$objectId.publish()');
-
+    startMonitor();
     _published = true;
     return true;
   }
@@ -209,8 +212,26 @@ abstract class LocalTrack extends Track {
     }
 
     logger.fine('$objectId.unpublish()');
-
+    stopMonitor();
     _published = false;
     return true;
   }
+
+  Timer? _monitorTimer;
+
+  Future<void> monitorSender();
+
+  @internal
+  void startMonitor() {
+    _monitorTimer ??=
+        Timer.periodic(const Duration(milliseconds: monitorFrequency), (_) {
+      monitorSender();
+    });
+  }
+
+  @internal
+  void stopMonitor() {
+    _monitorTimer?.cancel();
+    _monitorTimer = null;
+  }
 }

lib/src/track/local/video.dart

@@ -1,9 +1,12 @@
+import 'package:collection/collection.dart';
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
 
+import '../../events.dart';
 import '../../logger.dart';
 import '../../proto/livekit_models.pb.dart' as lk_models;
 import '../../types/other.dart';
 import '../options.dart';
+import '../stats.dart';
 import '../track.dart';
 import 'audio.dart';
 import 'local.dart';
@@ -15,6 +18,99 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   @override
   covariant VideoCaptureOptions currentOptions;
 
+  num? _currentBitrate;
+  get currentBitrate => _currentBitrate;
+  Map<String, VideoSenderStats>? prevStats;
+  final Map<String, num> _bitrateFoLayers = {};
+
+  @override
+  Future<void> monitorSender() async {
+    if (sender == null) {
+      _currentBitrate = 0;
+      return;
+    }
+    List<VideoSenderStats> stats = [];
+    try {
+      stats = await getSenderStats();
+    } catch (e) {
+      logger.warning('Failed to get sender stats: $e');
+      return;
+    }
+    Map<String, VideoSenderStats> statsMap = {};
+
+    for (var s in stats) {
+      statsMap[s.rid ?? 'f'] = s;
+    }
+
+    if (prevStats != null) {
+      num totalBitrate = 0;
+      statsMap.forEach((key, s) {
+        final prev = prevStats![key];
+        var bitRateForlayer = computeBitrateForSenderStats(s, prev).toInt();
+        _bitrateFoLayers[key] = bitRateForlayer;
+        totalBitrate += bitRateForlayer;
+      });
+      _currentBitrate = totalBitrate;
+      events.emit(VideoSenderStatsEvent(
+        stats: statsMap,
+        currentBitrate: currentBitrate,
+        bitrateForLayers: _bitrateFoLayers,
+      ));
+    }
+
+    prevStats = statsMap;
+  }
+
+  Future<List<VideoSenderStats>> getSenderStats() async {
+    if (sender == null) {
+      return [];
+    }
+
+    final stats = await sender!.getStats();
+    List<VideoSenderStats> items = [];
+    for (var v in stats) {
+      if (v.type == 'outbound-rtp') {
+        VideoSenderStats vs = VideoSenderStats(v.id, v.timestamp);
+        vs.frameHeight = getNumValFromReport(v.values, 'frameHeight');
+        vs.frameWidth = getNumValFromReport(v.values, 'frameWidth');
+        vs.framesPerSecond = getNumValFromReport(v.values, 'framesPerSecond');
+        vs.firCount = getNumValFromReport(v.values, 'firCount');
+        vs.pliCount = getNumValFromReport(v.values, 'pliCount');
+        vs.nackCount = getNumValFromReport(v.values, 'nackCount');
+        vs.packetsSent = getNumValFromReport(v.values, 'packetsSent');
+        vs.bytesSent = getNumValFromReport(v.values, 'bytesSent');
+        vs.framesSent = getNumValFromReport(v.values, 'framesSent');
+        vs.rid = getStringValFromReport(v.values, 'rid');
+        vs.encoderImplementation =
+            getStringValFromReport(v.values, 'encoderImplementation');
+        vs.retransmittedPacketsSent =
+            getNumValFromReport(v.values, 'retransmittedPacketsSent');
+        vs.qualityLimitationReason =
+            getStringValFromReport(v.values, 'qualityLimitationReason');
+        vs.qualityLimitationResolutionChanges =
+            getNumValFromReport(v.values, 'qualityLimitationResolutionChanges');
+
+        // locate the appropriate remote-inbound-rtp item
+        final remoteId = getStringValFromReport(v.values, 'remoteId');
+        final r = stats.firstWhereOrNull((element) => element.id == remoteId);
+        if (r != null) {
+          vs.jitter = getNumValFromReport(r.values, 'jitter');
+          vs.packetsLost = getNumValFromReport(r.values, 'packetsLost');
+          vs.roundTripTime = getNumValFromReport(r.values, 'roundTripTime');
+        }
+        final c = stats.firstWhereOrNull((element) => element.type == 'codec');
+        if (c != null) {
+          vs.mimeType = getStringValFromReport(c.values, 'mimeType');
+          vs.payloadType = getNumValFromReport(c.values, 'payloadType');
+          vs.channels = getNumValFromReport(c.values, 'channels');
+          vs.clockRate = getNumValFromReport(c.values, 'clockRate');
+        }
+        items.add(vs);
+      }
+    }
+    return items;
+  }
+
   // Private constructor
   LocalVideoTrack._(
     String name,
@@ -34,7 +130,7 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   static Future<LocalVideoTrack> createCameraTrack([
     CameraCaptureOptions? options,
   ]) async {
-    options ??= const CameraCaptureOptions();
+    options = const CameraCaptureOptions();
 
     final stream = await LocalTrack.createStream(options);
     return LocalVideoTrack._(
@@ -53,7 +149,7 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   static Future<LocalVideoTrack> createScreenShareTrack([
     ScreenShareCaptureOptions? options,
   ]) async {
-    options ??= const ScreenShareCaptureOptions();
+    options = const ScreenShareCaptureOptions();
 
     final stream = await LocalTrack.createStream(options);
     return LocalVideoTrack._(
@@ -73,7 +169,7 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   static Future<List<LocalTrack>> createScreenShareTracksWithAudio([
     ScreenShareCaptureOptions? options,
   ]) async {
-    options ??= const ScreenShareCaptureOptions(captureScreenAudio: true);
+    options = const ScreenShareCaptureOptions(captureScreenAudio: true);
 
     final stream = await LocalTrack.createStream(options);
 

lib/src/track/remote/audio.dart

@@ -1,10 +1,13 @@
+import 'package:collection/collection.dart';
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
 
+import '../../events.dart';
 import '../../internal/events.dart';
 import '../../proto/livekit_models.pb.dart' as lk_models;
 import '../../types/other.dart';
 import '../audio_management.dart';
 import '../local/local.dart';
+import '../stats.dart';
 import 'remote.dart';
 
 import '../web/_audio_api.dart' if (dart.library.html) '../web/_audio_html.dart'
@@ -58,4 +61,72 @@ class RemoteAudioTrack extends RemoteTrack
     audio.setSinkId(getCid(), deviceId);
     _deviceId = deviceId;
   }
+
+  AudioReceiverStats? prevStats;
+  num? _currentBitrate;
+  get currentBitrate => _currentBitrate;
+
+  @override
+  Future<void> monitorReceiver() async {
+    if (receiver == null) {
+      _currentBitrate = 0;
+      return;
+    }
+    final stats = await getReceiverStats();
+
+    if (stats != null && prevStats != null && receiver != null) {
+      _currentBitrate = computeBitrateForReceiverStats(stats, prevStats);
+      events.emit(AudioReceiverStatsEvent(
+          stats: stats, currentBitrate: currentBitrate));
+    }
+
+    prevStats = stats;
+  }
+
+  Future<AudioReceiverStats?> getReceiverStats() async {
+    if (receiver == null) {
+      return null;
+    }
+
+    final stats = await receiver!.getStats();
+    AudioReceiverStats? receiverStats;
+    for (var v in stats) {
+      if (v.type == 'inbound-rtp') {
+        receiverStats ??= AudioReceiverStats(v.id, v.timestamp);
+
+        receiverStats.jitter = getNumValFromReport(v.values, 'jitter');
+        receiverStats.packetsLost =
+            getNumValFromReport(v.values, 'packetsLost');
+        receiverStats.jitterBufferDelay =
+            getNumValFromReport(v.values, 'jitterBufferDelay');
+        receiverStats.bytesReceived =
+            getNumValFromReport(v.values, 'bytesReceived');
+        receiverStats.packetsReceived =
+            getNumValFromReport(v.values, 'packetsReceived');
+        receiverStats.concealedSamples =
+            getNumValFromReport(v.values, 'concealedSamples');
+        receiverStats.concealmentEvents =
+            getNumValFromReport(v.values, 'concealmentEvents');
+        receiverStats.silentConcealedSamples =
+            getNumValFromReport(v.values, 'silentConcealedSamples');
+        receiverStats.silentConcealmentEvents =
+            getNumValFromReport(v.values, 'silentConcealmentEvents');
+        receiverStats.totalAudioEnergy =
+            getNumValFromReport(v.values, 'totalAudioEnergy');
+        receiverStats.totalSamplesDuration =
+            getNumValFromReport(v.values, 'totalSamplesDuration');
+
+        final c = stats.firstWhereOrNull((element) => element.type == 'codec');
+        if (c != null) {
+          receiverStats.mimeType = getStringValFromReport(c.values, 'mimeType');
+          receiverStats.payloadType =
+              getNumValFromReport(c.values, 'payloadType');
+          receiverStats.channels = getNumValFromReport(c.values, 'channels');
+          receiverStats.clockRate = getNumValFromReport(c.values, 'clockRate');
+        }
+        break;
+      }
+    }
+    return receiverStats;
+  }
 }

lib/src/track/remote/remote.dart

@@ -1,7 +1,11 @@
+import 'dart:async';
+
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
+import 'package:meta/meta.dart';
 
 import '../../proto/livekit_models.pb.dart' as lk_models;
 import '../../types/other.dart';
+import '../stats.dart';
 import '../track.dart';
 
 abstract class RemoteTrack extends Track {
@@ -22,6 +26,7 @@ abstract class RemoteTrack extends Track {
     final didStart = await super.start();
     if (didStart) {
       await enable();
+      startMonitor();
     }
     return didStart;
   }
@@ -32,6 +37,25 @@ abstract class RemoteTrack extends Track {
     if (didStop) {
       await disable();
     }
+    stopMonitor();
     return didStop;
   }
+
+  Timer? _monitorTimer;
+
+  Future<void> monitorReceiver();
+
+  @internal
+  void startMonitor() {
+    _monitorTimer ??=
+        Timer.periodic(const Duration(milliseconds: monitorFrequency), (_) {
+      monitorReceiver();
+    });
+  }
+
+  @internal
+  void stopMonitor() {
+    _monitorTimer?.cancel();
+    _monitorTimer = null;
+  }
 }

lib/src/track/remote/video.dart

@@ -1,12 +1,15 @@
+import 'package:collection/collection.dart';
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
+import 'package:meta/meta.dart';
 
+import '../../events.dart';
 import '../../proto/livekit_models.pb.dart' as lk_models;
 import '../../types/other.dart';
 import '../local/local.dart';
+import '../stats.dart';
 import 'remote.dart';
 
 class RemoteVideoTrack extends RemoteTrack with VideoTrack {
-  //
   RemoteVideoTrack(String name, TrackSource source, rtc.MediaStream stream,
       rtc.MediaStreamTrack track,
       {rtc.RTCRtpReceiver? receiver})
@@ -18,4 +21,81 @@ class RemoteVideoTrack extends RemoteTrack with VideoTrack {
           track,
           receiver: receiver,
         );
+
+  VideoReceiverStats? prevStats;
+  num? _currentBitrate;
+  get currentBitrate => _currentBitrate;
+
+  @internal
+  String? getDecoderImplementation() {
+    return prevStats?.decoderImplementation;
+  }
+
+  @override
+  Future<void> monitorReceiver() async {
+    if (receiver == null) {
+      _currentBitrate = 0;
+      return;
+    }
+    final stats = await getReceiverStats();
+
+    if (stats != null && prevStats != null && receiver != null) {
+      _currentBitrate = computeBitrateForReceiverStats(stats, prevStats);
+      events.emit(VideoReceiverStatsEvent(
+          stats: stats, currentBitrate: currentBitrate));
+    }
+
+    prevStats = stats;
+  }
+
+  Future<VideoReceiverStats?> getReceiverStats() async {
+    if (receiver == null) {
+      return null;
+    }
+
+    final stats = await receiver!.getStats();
+    VideoReceiverStats? receiverStats;
+    for (var v in stats) {
+      if (v.type == 'inbound-rtp') {
+        receiverStats ??= VideoReceiverStats(v.id, v.timestamp);
+        receiverStats.jitter = getNumValFromReport(v.values, 'jitter');
+        receiverStats.jitterBufferDelay =
+            getNumValFromReport(v.values, 'jitterBufferDelay');
+        receiverStats.bytesReceived =
+            getNumValFromReport(v.values, 'bytesReceived');
+        receiverStats.packetsLost =
+            getNumValFromReport(v.values, 'packetsLost');
+        receiverStats.framesDecoded =
+            getNumValFromReport(v.values, 'framesDecoded');
+        receiverStats.framesDropped =
+            getNumValFromReport(v.values, 'framesDropped');
+        receiverStats.framesReceived =
+            getNumValFromReport(v.values, 'framesReceived');
+        receiverStats.packetsReceived =
+            getNumValFromReport(v.values, 'packetsReceived');
+        receiverStats.framesPerSecond =
+            getNumValFromReport(v.values, 'framesPerSecond');
+        receiverStats.frameWidth = getNumValFromReport(v.values, 'frameWidth');
+        receiverStats.frameHeight =
+            getNumValFromReport(v.values, 'frameHeight');
+        receiverStats.pliCount = getNumValFromReport(v.values, 'pliCount');
+        receiverStats.firCount = getNumValFromReport(v.values, 'firCount');
+        receiverStats.nackCount = getNumValFromReport(v.values, 'nackCount');
+        receiverStats.decoderImplementation =
+            getStringValFromReport(v.values, 'decoderImplementation');
+
+        final c = stats.firstWhereOrNull((element) => element.type == 'codec');
+        if (c != null) {
+          receiverStats.mimeType = getStringValFromReport(c.values, 'mimeType');
+          receiverStats.payloadType =
+              getNumValFromReport(c.values, 'payloadType');
+          receiverStats.channels = getNumValFromReport(c.values, 'channels');
+          receiverStats.clockRate = getNumValFromReport(c.values, 'clockRate');
+        }
+        break;
+      }
+    }
+
+    return receiverStats;
+  }
 }

lib/src/track/stats.dart

@@ -0,0 +1,200 @@
+import 'package:flutter/foundation.dart';
+
+import '../proto/livekit_models.pb.dart';
+
+const monitorFrequency = 2000;
+
+class CodecStats {
+  String? mimeType;
+  num? payloadType;
+  num? channels;
+  num? clockRate;
+}
+
+// key stats for senders and receivers
+class SenderStats extends CodecStats {
+  SenderStats(this.streamId, this.timestamp);
+
+  /// number of packets sent
+  num? packetsSent;
+
+  /// number of bytes sent
+  num? bytesSent;
+
+  /// jitter as perceived by remote
+  num? jitter;
+
+  /// packets reported lost by remote
+  num? packetsLost;
+
+  /// RTT reported by remote
+  num? roundTripTime;
+
+  /// ID of the outbound stream
+  String streamId;
+
+  String? encoderImplementation;
+
+  num timestamp;
+}
+
+class AudioSenderStats extends SenderStats {
+  AudioSenderStats(String streamId, num timestamp) : super(streamId, timestamp);
+  TrackType type = TrackType.AUDIO;
+}
+
+class VideoSenderStats extends SenderStats {
+  VideoSenderStats(String streamId, num timestamp) : super(streamId, timestamp);
+  TrackType type = TrackType.VIDEO;
+
+  num? firCount;
+
+  num? pliCount;
+
+  num? nackCount;
+
+  String? rid;
+
+  num? frameWidth;
+
+  num? frameHeight;
+
+  num? framesSent;
+
+  num? framesPerSecond;
+
+  // bandwidth, cpu, other, none
+  String? qualityLimitationReason;
+
+  num? qualityLimitationResolutionChanges;
+
+  num? retransmittedPacketsSent;
+}
+
+class ReceiverStats extends CodecStats {
+  ReceiverStats(this.streamId, this.timestamp);
+  num? jitterBufferDelay;
+
+  /// packets reported lost by remote
+  num? packetsLost;
+
+  /// number of packets sent
+  num? packetsReceived;
+
+  num? bytesReceived;
+
+  String streamId;
+
+  num? jitter;
+
+  num timestamp;
+}
+
+class AudioReceiverStats extends ReceiverStats {
+  AudioReceiverStats(String streamId, num timestamp)
+      : super(streamId, timestamp);
+  TrackType type = TrackType.AUDIO;
+
+  num? concealedSamples;
+
+  num? concealmentEvents;
+
+  num? silentConcealedSamples;
+
+  num? silentConcealmentEvents;
+
+  num? totalAudioEnergy;
+
+  num? totalSamplesDuration;
+}
+
+class VideoReceiverStats extends ReceiverStats {
+  VideoReceiverStats(String streamId, num timestamp)
+      : super(streamId, timestamp);
+
+  TrackType type = TrackType.VIDEO;
+
+  num? framesDecoded;
+
+  num? framesDropped;
+
+  num? framesReceived;
+
+  num? framesPerSecond;
+
+  num? frameWidth;
+
+  num? frameHeight;
+
+  num? firCount;
+
+  num? pliCount;
+
+  num? nackCount;
+
+  String? decoderImplementation;
+}
+
+num computeBitrateForSenderStats(
+  SenderStats currentStats,
+  SenderStats? prevStats,
+) {
+  if (prevStats == null) {
+    return 0;
+  }
+  num? bytesNow;
+  num? bytesPrev;
+  bytesNow = currentStats.bytesSent;
+  bytesPrev = prevStats.bytesSent;
+  if (bytesNow == null || bytesPrev == null) {
+    return 0;
+  }
+  if (kIsWeb) {
+    return ((bytesNow - bytesPrev) * 8) /
+        (currentStats.timestamp - prevStats.timestamp);
+  }
+
+  return ((bytesNow - bytesPrev) * 8 * 1000) /
+      (currentStats.timestamp - prevStats.timestamp);
+}
+
+num computeBitrateForReceiverStats(
+  ReceiverStats currentStats,
+  ReceiverStats? prevStats,
+) {
+  if (prevStats == null) {
+    return 0;
+  }
+  num? bytesNow;
+  num? bytesPrev;
+
+  bytesNow = currentStats.bytesReceived;
+  bytesPrev = prevStats.bytesReceived;
+
+  if (bytesNow == null || bytesPrev == null) {
+    return 0;
+  }
+  if (kIsWeb) {
+    return ((bytesNow - bytesPrev) * 8) /
+        (currentStats.timestamp - prevStats.timestamp);
+  }
+
+  return ((bytesNow - bytesPrev) * 8 * 1000) /
+      (currentStats.timestamp - prevStats.timestamp);
+}
+
+num? getNumValFromReport(Map<dynamic, dynamic> values, String key) {
+  if (values.containsKey(key)) {
+    return (values[key] is String)
+        ? num.tryParse(values[key])
+        : values[key] as num;
+  }
+  return null;
+}
+
+String? getStringValFromReport(Map<dynamic, dynamic> values, String key) {
+  if (values.containsKey(key)) {
+    return values[key] as String;
+  }
+  return null;
+}