dequeue method
dynamic
dequeue()
Implementation
dequeue() {
// If the current snack bar is being transitioned in or displayed, cancel it
// and advance it to transition out.
if (_currentSnackBarState == SnackBarState.transitionIn ||
_currentSnackBarState == SnackBarState.display) {
_currentSnackBarTimer!.cancel();
_currentSnackBarTimer = null;
_currentSnackBarState = SnackBarState.display;
_advance();
}
}