unregister
Send an unregistration request for the instance to the saved distributor and remove the registration. Remove the distributor if this is the last instance registered.
MessagingReceiver.onUnregistered won't be called after that request.
Parameters
context
To interact with the shared preferences and send broadcast intents.
instance
Registration instance. Can be used to get multiple registrations, eg. for multi-account support.
unregister with additional KeyManager parameter.
Parameters
keyManager
To manager web push keys. By default: DefaultKeyManager.