log pid

Worker.php

@@ -1297,7 +1297,7 @@ class Worker
         if (!self::$daemonize) {
             echo $msg;
         }
-        file_put_contents(self::$logFile, date('Y-m-d H:i:s') . " " . $msg, FILE_APPEND | LOCK_EX);
+        file_put_contents(self::$logFile, date('Y-m-d H:i:s') . ' ' . 'pid:'. posix_getpid() . ' ' . $msg, FILE_APPEND | LOCK_EX);
     }
 
     /**