While working on the DevTools profiler, I've noticed that durations are sometimes incorrect. This seems to be vaguely related to high/low priority state updates. Need to track this down more so I'm filing an issue for myself.
this.lastEffect = null;
  this.expirationTime = NoWork;
  this.childExpirationTime = NoWork;
  this.alternate = null;
  if (enableProfilerTimer) {
    this.actualDuration = 0;
    this.actualStartTime = 0;
    this.selfBaseDuration = 0;
    this.treeBaseDuration = 0;
  }
  if (__DEV__) {
    this._debugID = debugCounter++;
    this._debugSource = null;
    this._debugOwner = null;
    this._debugIsCurrentlyTiming = false;
    if (!hasBadMapPolyfill && typeof Object.preventExtensions === 'function') {
      Object.preventExtensions(this);
    }
  }
}
const createFiber = function(
  tag: TypeOfWork,
  pendingProps: mixed,
  key: null | string,
  mode: TypeOfMode,
): Fiber {
  
  return new FiberNode(tag, pendingProps, key, mode);
};
function shouldConstruct(Component) {