listen method
Calls stream.listen
and sets subscription.
Returns false
if already listening.
Implementation
bool listen() {
if (isListening) return false;
if (stream is EventStream) {
var eventStream = stream as EventStream;
_subscription = eventStream.listen(
onDataWrapper as void Function(Object?),
onError: onErrorWrapper,
onDone: onDoneWrapper,
cancelOnError: cancelOnError,
singletonIdentifier: singletonIdentifier,
singletonIdentifyByInstance: singletonIdentifyByInstance)
as StreamSubscription<T>?;
} else {
_subscription = stream.listen(onDataWrapper,
onError: onErrorWrapper,
onDone: onDoneWrapper,
cancelOnError: cancelOnError);
}
return _subscription != null;
}