Note, that closing a channel after this function had suspended does not cause this suspended send invocation to abort, because closing a channel is conceptually like sending a special “close token” over this channel. All elements that are sent over the channel are delivered in first-in first-out order. The element that is being sent will get delivered to receivers before a close token.
Cancellation of suspended send is atomic – when this function throws CancellationException it means that the element was not sent to this channel. As a side-effect of atomic cancellation, a thread-bound coroutine (to some UI thread, for example) may continue to execute even after it was cancelled from the same thread in the case when this send operation was already resumed and the continuation was posted for execution to the thread’s queue.