It's probably not news to anyone that crossbeam is effectively unmaintained right now. I simply do not have the time to keep up with it.
At the same time, i think these kinds of concurrent data structures are very important, and would love to see continuing work on the library.
This is a plea for help. If you are interested in getting involved in the maintenance of the library, please let me know on this thread. Ideally, we can get a handful of people together to share the load.