The destination is chosen randomly among the InnerPQs that are not being
operated on by other threads. Elements should be well-distributed under low
contention, and also under high contention if the distribution of inserted
elements is similar between threads.
Inserts an element into one of the InnerPQs.
The destination is chosen randomly among the InnerPQs that are not being operated on by other threads. Elements should be well-distributed under low contention, and also under high contention if the distribution of inserted elements is similar between threads.