I'm not a big fan of this. If length(NodePids) gets large this is going to start creating a lot of garbage as well as slow down during the copying out of ets.

There is a select_count/2 that we might be able to use but I'm wondering if we might not want to store the actual count somehow.

Also, I was contemplating starting one of these governor servers per node. That could also help splitting up some of the logic into a couple modules. If we had a "rexi_governor_manager" that handled all the node up/down logic and started a govenor for every node in mem3:nodes() then each of those would be a single destination thing which might also simplify some of the ets based process tracking.