Use hrtime() instead of microtime() for timing things

Prem Suthar → made their first commit to this issue’s fork.

The API for hrtime() is different, see https://www.php.net/manual/en/function.hrtime.php so can't just swap on for one but need to handle the return value differently too.

I have Updated The code as per hrtime() api plz review it.

Test-failures (a lot of them as well...)