Pony's new allocator fixes unbounded memory growth, thread by thread
Randomized TCP stress tests surfaced memory leaks the old allocator had hidden: blocks freed cross-thread never reclaimed, 32-byte slots stuck forever, and adjacent blocks never merged. The fix, inspired by snmalloc, gives each thread its own region-based arenas so memory can be merged and returned to the OS. A leaked-postmortem worth reading before your next allocator design.