handle exit single process in pool

[pilot114]

$manager = new \Ko\ProcessManager();
        for ($i = 0; $i < 10; $i++) {
            $manager->fork(function(\Ko\Process $p) use ($i) {
                echo 'Hello from ' . $p->getPid();
                sleep(1);
            })->onSuccess(function() {
                echo 'end';
            })->onError(function() {
                echo 'fail end';
            });
        }
$manager->wait();

OnSuccess / onError callbacks don't work if call wait() on process manager. If call wait () for each process handles call correct, but not parallel