/**
* Returns an observable that emits a value every $interval milliseconds after (up to $count times). The value emitted
* is an integer of the number of times the observable emitted a value.
*
* @param int $interval Time interval between emitted values in milliseconds.
* @param int $count Number of values to emit. PHP_INT_MAX by default.
*
* @return \Amp\Observable
*
* @throws \Error If the number of times to emit is not a positive value.
*/
function interval(int $interval, int $count = PHP_INT_MAX) : Observable
{
if (0 >= $count) {
throw new \Error("The number of times to emit must be a positive value");
}
$postponed = new Postponed();
Loop::repeat($interval, function ($watcher) use(&$i, $postponed, $count) {
$postponed->emit(++$i);
if ($i === $count) {
Loop::cancel($watcher);
$postponed->resolve();
}
});
return $postponed->observe();
}
