An interface implemented by classes that can vend Ticker objects.
Tickers can be used by any object that wants to be notified whenever a frame triggers, but are most commonly used indirectly via an AnimationController. AnimationControllers need a TickerProvider to obtain their Ticker. If you are creating an AnimationController from a State, then you can use the TickerProviderStateMixin and SingleTickerProviderStateMixin classes to obtain a suitable TickerProvider. The widget test framework WidgetTester object can be used as a ticker provider in the context of tests. In other contexts, you will have to either pass a TickerProvider from a higher level (e.g. indirectly from a State that mixes in TickerProviderStateMixin), or create a custom TickerProvider subclass.
Abstract const constructor. This constructor enables subclasses to provide
const constructors so that they can be used in const expressions.