forwardRewind method

@override void forwardRewind(double speed)

Implementation

@override
void forwardRewind(double speed) {
  pause();
  channel.invokeMethod(WebPlayer.methodForwardRewindSpeed, speed);
  forwardHandler?.stop();
  forwardHandler = ForwardHandler();
  _listenPosition(); // for this usecase, enable listen position
  forwardHandler?.start(this, speed);
}