Sandbox: https://codesandbox.io/s/cranky-kapitsa-op3jh

Repro: type "a" and then after a second "b"

Expected: Eventually you'll see "ab" in all fields. Pending "..." indicator goes away.

Actual: You'll keep seeing "a" in low pri field. Pending "..." indicator is stuck.
validateNotInFunctionRender() &&
          validateEventListenerTarget(target, callback)
        ) {
          let listener = listenerMap.get(target);
          if (listener === undefined) {
            if (callback == null) {
              return;
            }
            listener = createReactListener(event, callback, target, destroy);
            listenerMap.set(target, listener);