Stimer, a timer with pause/resume feature.

And immediately proceed to the samples:

Regular timer:

$loop = Factory::create();
$interval = 5;
$timer = new Timer($loop, $interval, function () { echo 'hello world'; });
// ... 3 seconds
$timer->pause();
$timer->getLeftInterval(); // ~ 2 seconds
// ... something happens
$timer->resume();
// ... 2 seconds
// hello world

Periodic timer:

$loop = Factory::create();
$interval = 5;
$timer = new PeriodicTimer($loop, $interval, function () { echo 'hello world'; });
// ... 3 seconds
$timer->pause();
$timer->getLeftInterval(); // ~ 2 seconds
// ... something happens
$timer->resume();
// ... 2 seconds
// hello world
// ... 5 seconds
// hello world