awaitSingle
Awaits the single value from the given Mono without blocking the thread and returns the resulting value, or, if this Mono has produced an error, throws the corresponding exception.
This suspending function is cancellable. If the Job of the current coroutine is cancelled while the suspending function is waiting, this function immediately cancels its Subscription and resumes with CancellationException.
Throws
if the Mono does not emit any value