Timer::add in master process is impossible ? I think it can be

At some situation i need add Timer at master process, but it look like imposible because master have `monitorWorkersForLinux` method with `pcntl_wait` function what will be block master process until worker will not shutdown or master will get somу signal. While it was blocking no one Event library can't run timer...but...

Some Event library has own `pcntl_wait` analogs , like `Swoole\Coroutine\System::wait` in Swoole (https://wiki.swoole.com/#/coroutine/system?id=wait). It will do same things as `pcntl_wait` but additional Timer can be work in master process

Is it possible change `monitorWorkersForLinux` ` $pid = \pcntl_wait($status, \WUNTRACED);`->`static::$globalEvent->wait()` ? And EventInterface need be abstract with share method `wait` by default have `pcntl_wait` (except Swoole) and return array `['pid'=>$pid, 'signal'=>$status]` (like a `Swoole\Coroutine\System::wait` return array's format) or stay like Interface but need have abstract method `wait():array` (but in this realisation each Event need `wait` method with `pcntl_wait` except Swoole)

Because not it impossible change `monitorWorkersForLinux` by extends class , because it have private property , additionaly this method have a lot of code, but only need change one line of code

@walkor

Start by reading monitorWorkersForLinux and EventInterface, focusing on the pcntl_wait call and how the master process runs timers. Determine whether the event abstraction can preserve worker monitoring while allowing master-process timers, then validate the chosen interface and behavior with the relevant existing event implementations and tests.

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