Good post. One thing I noted is that persistent_term copy on write is the least problem of writing. Rewriting or deleting an entry in persistent_term triggers global garbage collection (global as in “in every process”). Since the data is not copied on read, processes store pointers to this data directly, not in their heap, but in this persistent_term storage. So when you change the entry, each process needs to copy the old value from the persistent term into their heap and replace the pointer to the heap one.

My experience reading this was:

Beginning: haha cute, this is aimed at newbies.
End: oh, really? I need to do more reading.