removeListener method
- SubscriptionListener listener
 
Removes a listener from the Subscription instance so that it will not receive events anymore.
Lifecycle a listener can be removed at any time.
- 
listenerThe listener to be removed. - 
See addListener
 
Implementation
void removeListener(SubscriptionListener listener) {
  var found = _listeners.remove(listener);
  if (found) {
    scheduleMicrotask(() {
      listener.onListenEnd();
    });
  }
}