It’s the responsibility of the caller to keep track of the returned Subscription and call
Subscription.unsubscribe to stop observing and avoid potentially leaking memory by keeping an unused Observer
registered. It’s is recommend to use one of the
observe extension methods that unsubscribe automatically.
The created Subscription is in paused state until explicitly resumed by calling Subscription.resume. While paused the Subscription will not receive any state updates. Once resumed the observer will get invoked immediately with the latest state.
Return A Subscription object that can be used to unsubscribe from further state changes.