if (shouldTrackSideEffects && newFiber.alternate === null) {
      newFiber.effectTag = Placement;
    }
    return newFiber;
  }
  function updateTextNode(
    returnFiber: Fiber,
    current: Fiber | null,
    textContent: string,
    expirationTime: ExpirationTime,
  ) {
    if (current === null || current.tag !== HostText) {
      
      const created = createFiberFromText(
        textContent,
        returnFiber.mode,
        expirationTime,
      );
      created.return = returnFiber;
      return created;
    } else {
      
      const existing = useFiber(current, textContent, expirationTime);
      existing.return = returnFiber;
      return existing;
    }
  }
  function updateElement(