The type of the data being observed.
Subscribe to changes on this object. When this observable detects a change, the
observerprovided will be called with the data associated with this observable.
A subscription that can be used to remove the subscribed observer.
Wait for a specific condition on this object to be met. When this observable detects a change, the
conditionprovided will be called. When the
conditionreturns true, the returned Promise will be resolved.
A promise that is resolved when