Module worker 

ZTS worker threads — each thread runs an independent PHP context.

A worker thread:

1. Registers with TSRM via ZtsThreadGuard
2. Starts a PHP request (request_startup)
3. Executes the PHP worker script (which registers handlers)
4. Enters the recv/send loop via bridge::do_recv()/bridge::do_send()
5. Cleans up on exit

Functions

spawn_zts_worker

Spawn a ZTS worker thread that executes the given PHP script.