Asynchronous queue interface.
An asynchronous semaphore, useful as a concurrency primitive.
A signal whose value may be set asynchronously.
A signal whose value may be set asynchronously. Provides continuous and discrete streams for responding to changes to it's value.
Asynchronous queue interface. Operations are all nonblocking in their implementations, but may be 'semantically' blocking. For instance, a queue may have a bound on its size, in which case enqueuing may block until there is an offsetting dequeue.