Add support for external thread events.
See asio_external_thread_event.h for details about usage.
This is the first version that compiled, the code was not executed even
once, but wanted to get it out early to unblock @hannesr. Thus the [RFC]
flag.
My next step is to implement asio-compatible equivalent of
fb_call_user_func_async() that will make it possible to easily test the
new functonality by simulating async stuff with sleep(), etc. on the PHP
side.
There are 2 major mostly lockless synchronization points that needs
careful review:
- queue of ready external thread events (asio_session.{cpp.h})
- shutdown cleanup (asio_external_thread_event.{cpp,h})
Jan Oravec
88687ba6f7