message: remove isset_event_callback
diff: static zend_class_entry swoole_redis_coro_ce;
  static zend_class_entry *swoole_redis_coro_class_entry_ptr;
  -static int isset_event_callback = 0;
  #define IS_EX_PX_ARG(a) (IS_EX_ARG(a) || IS_PX_ARG(a))
  #define IS_NX_XX_ARG(a) (IS_NX_ARG(a) || IS_XX_ARG(a))
  @@ -1053,12 +1052,11 @@ static PHP_METHOD(swoole_redis_coro, connect)
  }
  php_swoole_check_reactor();
  - if (!isset_event_callback)
  + if (!swReactor_handle_isset(SwooleG.main_reactor, PHP_SWOOLE_FD_REDIS))
  {
  SwooleG.main_reactor->setHandle(SwooleG.main_reactor, PHP_SWOOLE_FD_REDIS | SW_EVENT_READ, swoole_redis_coro_onRead);
  SwooleG.main_reactor->setHandle(SwooleG.main_reactor, PHP_SWOOLE_FD_REDIS | SW_EVENT_WRITE, swoole_redis_coro_onWrite);
  SwooleG.main_reactor->setHandle(SwooleG.main_reactor, PHP_SWOOLE_FD_REDIS | SW_EVENT_ERROR, swoole_redis_coro_onError);
  - isset_event_callback = 1;
  }
  redisAsyncSetConnectCallback(context, swoole_redis_coro_onConnect);
  