cancel method
Cancels the current listen for speech if active, does nothing if not.
Canceling means that there will be no final result returned from the
recognizer. Each listen session should be ended with either stop or
cancel, for example in the dispose method of a Widget. cancel is
automatically invoked by a permanent error if cancelOnError
is set
to true in the listen call.
Note Cannot be used until a successful initialize call. Should only be used after a successful listen call.
Implementation
@override
Future<void> cancel() async {
if (null == _webSpeech) return;
_webSpeech!.abort();
}