Converts this job to the hot reactive completable that signals with onCompleted when the corresponding job completes.
Every subscriber gets the signal at the same time. Unsubscribing from the resulting completable does not affect the original job in any way.
Note: This is an experimental api. Conversion of coroutines primitives to reactive entities may change in the future to account for the concept of structured concurrency.
-- the coroutine context from which the resulting completable is going to be signalled