New UV based event loop (ext-uv).
(#112 by @WyriHaximus)

Use high resolution timer on PHP 7.3+.
(#182 by @clue)

Improve PCNTL signals by using async signal dispatching if available.
(#179 by @CharlotteDunois)

Improve test suite and test suite set up.
(#174 by @WyriHaximus, #181 by @clue)

Fix PCNTL signals edge case.
(#183 by @clue)