Beyond AMPHP, there is also ReactPHP, Swoole and Hyperf. AMPHP seems most relevant though.
Another complexity is right now to use AMPHP we'd have to plug in its modules to replace core querying and HTTP functionality in relevant cases, which would complicate things, be a lot of work, and potentially hurt performance in different ways.
Another complexity is right now to use AMPHP we'd have to plug in its modules to replace core querying and HTTP functionality in relevant cases, which would complicate things, be a lot of work, and potentially hurt performance in different ways.