copiable, thus fixing the unit tests with a custom trivially copyable type.
the indices allowing rescheduling of values in the middle of the queue. 2) Implemented a cache friendly variant - MutableSkipHeapPriorityQueue based on https://playfulprogramming.blogspot.com/2015/08/cache-optimizing-priority-queue.html https://github.com/rollbear/prio_queue/blob/master/prio_queue.hpp