message: Remove Swoole\Timer::del (revert the part of 8f22b9e).
  The reason:
diff: @@ -199,7 +199,6 @@ const zend_function_entry swoole_functions[] =
  PHP_FE(swoole_timer_tick, arginfo_swoole_timer_tick)
  PHP_FE(swoole_timer_exists, arginfo_swoole_timer_exists)
  PHP_FE(swoole_timer_clear, arginfo_swoole_timer_clear)
  - PHP_FALIAS(swoole_timer_del, swoole_timer_clear, arginfo_swoole_timer_clear)
  /*------swoole_async_io------*/
  PHP_FE(swoole_async_set, arginfo_swoole_async_set)
  PHP_FE(swoole_async_read, arginfo_swoole_async_read)
  @@ -234,7 +233,6 @@ static const zend_function_entry swoole_timer_methods[] =
  ZEND_FENTRY(after, ZEND_FN(swoole_timer_after), arginfo_swoole_timer_after, ZEND_ACC_PUBLIC | ZEND_ACC_STATIC)
  ZEND_FENTRY(exists, ZEND_FN(swoole_timer_exists), arginfo_swoole_timer_exists, ZEND_ACC_PUBLIC | ZEND_ACC_STATIC)
  ZEND_FENTRY(clear, ZEND_FN(swoole_timer_clear), arginfo_swoole_timer_clear, ZEND_ACC_PUBLIC | ZEND_ACC_STATIC)
  - ZEND_FENTRY(del, ZEND_FN(swoole_timer_clear), arginfo_swoole_timer_clear, ZEND_ACC_PUBLIC | ZEND_ACC_STATIC)
  PHP_FE_END
  };
  