Returns true if there are threads waiting to take instances from this deque. See disclaimer on accuracy in
{@link java.util.concurrent.locks.ReentrantLock#hasWaiters(Condition)}.
@return true if there is at least one thread waiting on this deque's notEmpty condition.
Returns true if there are threads waiting to take instances from this deque. See disclaimer on accuracy in {@link java.util.concurrent.locks.ReentrantLock#hasWaiters(Condition)}.
@return true if there is at least one thread waiting on this deque's notEmpty condition.