Converts this deferred value to the instance of CompletableFuture.
The deferred value is cancelled when the resulting future is cancelled or otherwise completed.
Converts this completion stage to an instance of Deferred.
When this completion stage is an instance of Future, then it is cancelled when
the resulting deferred is cancelled.
Starts new coroutine and returns its result as an implementation of CompletableFuture.
The running coroutine is cancelled when the resulting future is cancelled or otherwise completed.