Signals that the given observable might have changed and an update potentially modifying that observable has started.
The method Observable.update can be used to force the observable to report the change.
Every call of this method must eventually be accompanied with the corresponding endUpdate call.
Signals that an update that potentially modified the given observable has ended. This is a good place to react to changes.
Signals that the given observable has changed.
This method should not attempt to get the value of the given observable or any other observables.
Optionalchange: TChangeSignals that the given observable might have changed.
The method Observable.update can be used to force the observable to report the change.
This method should not attempt to get the value of the given observable or any other observables.
Represents an observer that can be subscribed to an observable.
If an observer is subscribed to an observable and that observable didn't signal a change through one of the observer methods, the observer can assume that the observable didn't change.
If an observable reported a possible change, Observable.update forces the observable to report the actual change if any.