setRemoteRenderParams method
Set remote image parameters
Parameters:
userId:   User ID
streamType:  Video stream type
- 
HD big image: TRTCCloudDef.TRTC_VIDEO_STREAM_TYPE_BIG 
- 
Smooth big image: TRTCCloudDef.TRTC_VIDEO_STREAM_TYPE_SMALL 
- 
Substream (screen sharing): TRTCCloudDef.TRTC_VIDEO_STREAM_TYPE_SUB 
renderParams: rendering parameters (fill mode, rotation angle, mirror mode, etc.). For more information, please see the definition of the TRTCRenderParams parameter in trtc_cloud_def.dart
Platform not supported:
- web
Implementation
Future<void> setRemoteRenderParams(
    String userId, int streamType, TRTCRenderParams renderParams) {
  if(Store.sharedInstance().userRenderParamsMap[userId] != null) {
    Store.sharedInstance().setUserRenderParamsMap(userId, renderParams);
  }
  return _cloudChannel!.invokeMethod('setRemoteRenderParams', {
    "userId": userId,
    "streamType": streamType,
    "param": jsonEncode(renderParams),
  });
}