message: Clear all of the response attributes before new request.
diff: @@ -191,6 +191,21 @@ static int http_client_coro_execute(zval *zobject, char *uri, zend_size_t uri_le
  return SW_ERR;
  }
  + // clear all when new request
  + zval *attr;
  + zend_update_property_long(swoole_http_client_coro_class_entry_ptr, zobject, ZEND_STRL("statusCode"), 0 TSRMLS_CC);
  + attr = sw_zend_read_property(swoole_http_client_coro_class_entry_ptr, zobject, ZEND_STRL("headers"), 1 TSRMLS_CC);
  + if (Z_TYPE_P(attr) == IS_ARRAY)
  + {
  + zend_hash_clean(Z_ARRVAL_P(attr));
  + }
  + attr = sw_zend_read_property(swoole_http_client_coro_class_entry_ptr, zobject, ZEND_STRL("set_cookie_headers"), 1 TSRMLS_CC);
  + if (Z_TYPE_P(attr) == IS_ARRAY)
  + {
  + zend_hash_clean(Z_ARRVAL_P(attr));
  + }
  + zend_update_property_string(swoole_http_client_coro_class_entry_ptr, zobject, ZEND_STRL("body"), "" TSRMLS_CC);
  +
  http_client *http = swoole_get_object(zobject);
  //http is not null when keeping alive
  