listen method
creates a disposable listener for stream
.
Implementation
void listen(AnimateToState owner, ValueChanged<AnimateToInput> callback) {
assert(
_debugOwner == null || _debugOwner == owner,
'AnimateToController can be used by only one AnimateTo widget.',
);
_debugOwner = owner;
_subscription = _streamController.stream.listen((event) {
callback(event);
});
}