Author: Vasily Zorin (maintainer@daemon.io)
Inheritance: extends Generic
 /**
  * spawn new master process.
  * @return null|integer - success
  */
 public static function spawnMaster()
 {
     Daemon::$masters->push($thread = new Thread\Master());
     $thread->start();
     if (-1 === $thread->getPid()) {
         Daemon::log('could not start master');
         exit(0);
     }
     return $thread->getPid();
 }