Awesome that you looked into this!
Have you been able to run any benchmarks? (Are there any benchmarks for this kind of thing?) IDK, seems kind of silly when talking about PHP and webservers but people were concerned when I suggested it in the original thread.
In particular, it is mentioned that the `Zend` allocator does not play well with fine-grained tracking (so would not have caught this issue?) and you need to swap to the system allocator.