closeSync method Null safety

void closeSync ()

Closes the controller and delivers a done event.

Closes the controller like close and attempts to deliver a "done" event immediately. Delivery can be delayed if other previously added events are still pending delivery, if the subscription is paused, or if the subscription isn't listening yet. If it's necessary to know whether the "done" event has been delievered, done future will complete when that has happened.


void closeSync();