I think maybe we should revert https://github.com/facebook/react/pull/5947.

People already think `proxyEvent` is some kind of an API: https://github.com/facebook/react/issues/12169.

It's also annoying to view in the debugger because none of the properties show up.

Instead, we could seal the event object or something like that.
!target.constructor.Interface.hasOwnProperty(prop) &&
              shouldBeReleasedProperties.indexOf(prop) === -1
            ) {
              warningWithoutStack(
                didWarnForAddedNewProperty || target.isPersistent(),
                "This synthetic event is reused for performance reasons. If you're " +
                  "seeing this, you're adding a new property in the synthetic event object. " +
                  'The property is never released. See ' +
                  'https://fb.me/react-event-pooling for more information.',
              );
              didWarnForAddedNewProperty = true;
            }
            target[prop] = value;
            return true;
          },
        });
      },
    });
    
  }
}
addEventPoolingTo(SyntheticEvent);
/**
 * Helper to nullify syntheticEvent instance properties when destructing
 *
 * @param {String} propName
 * @param {?object} getVal
 * @return {object} defineProperty object
 */
function getPooledWarningPropertyDefinition(propName, getVal) {