time_nanosleep() might return an array. If it does, it contains seconds and nanoseconds. https://www.php.net/manual/en/function.time-nanosleep.php

However, PHPStan thinks accessing this is an error:

https://phpstan.org/r/e1b5c862-77ed-479e-abca-ba6a77e3df76

Offset 'nanoseconds' does not exist on array{int<0, max>, int<0, max>}.
Offset 'seconds' does not exist on array{int<0, max>, int<0, max>}.