Allows a single fiber to wait to be notified by another fiber in the same domain. If multiple fibers need to wait at once, or the notification comes from another domain, this can't be used.
A handle representing a fiber that might be sleeping. It is either in the Running or Sleeping state.
val create : unit -> 'a tcreate () is a new waiter, initially in the Running state.
wake t v resumes t's fiber with value v and returns true if it was sleeping. If t is Running then this just returns false.
val wake_if_sleeping : unit t -> unitwake_if_sleeping is ignore (wake t (Ok ())).
val await : 'a t -> string -> int -> 'aawait t op id suspends the calling fiber, changing t's state to Sleeping. If the fiber is cancelled, a cancel exception is raised. op and id are used for tracing.