doOnPause method
Invokes the given callback function when the stream subscription is paused.
Example
final subscription = Stream.fromIterable([1])
  .doOnPause(() => print('Gimme a minute please'))
  .listen(null);
subscription.pause(); // prints 'Gimme a minute please'
Implementation
Stream<T> doOnPause(void Function() onPause) =>
    DoStreamTransformer<T>(onPause: onPause).bind(this);