Flutter code error - I am integrating (webrtc using nodejs) in flutter - node.js

Question

C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_webrtc-0.8.12/lib/src/native/rtc_video_renderer_impl.dart:11:7: Error: The non-abstract class 'RTCVideoRenderer' is missing implementations for these members:
- VideoRenderer.onFirstFrameRendered
Try to either
- provide an implementation,
- inherit an implementation from a superclass or mixin,
- mark the class as abstract, or
- provide a 'noSuchMethod' implementation.
class RTCVideoRenderer extends ValueNotifier<RTCVideoValue>
^^^^^^^^^^^^^^^^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/webrtc_interface-1.0.8/lib/src/rtc_video_renderer.dart:51:13: Context: 'VideoRenderer.onFirstFrameRendered' is defined here.
Function? onFirstFrameRendered;
^^^^^^^^^^^^^^^^^^^^
FAILURE: Build failed with an exception.
* Where:
Script 'C:\src\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 1159
* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command 'C:\src\flutter\bin\flutter.bat'' finished with non-zero exit value 1
* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 7s
Exception: Gradle task assembleDebug failed with exit code 1
pls help me out
pls help me
to solve this error
flutter with webrtc using nodejs
Flutter code error - I am integrating (webrtc using nodejs) in flutter