Calls the given teardown function when the subscriber unsubscribes. Completion and an error send by the observable will lead to unsubscribing and therefore also trigger a call of the given teardown function.
function that should be called
Calls the given teardown function when the subscriber unsubscribes. Completion and an error send by the observable will lead to unsubscribing and therefore also trigger a call of the given teardown function.