A Condition Variable for Tokio

Not Cancellation-Safe: If your future gets canceled while inside wait, no other future may get woken up.

Spurious Wakeups Possible: Like any condition variable, there can be spurious wakeups, so always re-check the condition after waking up. Note that, because this crate uses tokio's Notify internally and its semantics are slightly different than those of condition variables, spurious wake ups are even more likely.

This is not part of the Tokio project: See the discussion here on why Tokio does not have a built-in Condvar implementation (yet).