Function logBlockingStart

packages/react-reconciler/src/ReactFiberPerformanceTrack.js:637–753

(
  updateTime: number,
  eventTime: number,
  eventType: null | string,
  eventIsRepeat: boolean,
  isSpawnedUpdate: boolean,
  isPingedUpdate: boolean,
  renderStartTime: number,
  lanes: Lanes,
  debugTask: null | ConsoleTask, // DEV-only
  updateMethodName: null | string,
  updateComponentName: null | string,
)

}

export function logBlockingStart(
  updateTime: number,
  eventTime: number,
  eventType: null | string,
  eventIsRepeat: boolean,
  isSpawnedUpdate: boolean,
  isPingedUpdate: boolean,
  renderStartTime: number,
  lanes: Lanes,
  debugTask: null | ConsoleTask, // DEV-only
  updateMethodName: null | string,
  updateComponentName: null | string,
): void {
  if (supportsUserTiming) {
    currentTrack = 'Blocking';
    // Clamp start times
    if (updateTime > 0) {
      if (updateTime > renderStartTime) {
        updateTime = renderStartTime;
      }
    } else {
      updateTime = renderStartTime;
    }
    if (eventTime > 0) {
      if (eventTime > updateTime) {
        eventTime = updateTime;
      }
    } else {
      eventTime = updateTime;
    }
    // If a blocking update was spawned within render or an effect, that's considered a cascading render.
    // If you have a second blocking update within the same event, that suggests multiple flushSync or
    // setState in a microtask which is also considered a cascade.
    if (eventType !== null && updateTime > eventTime) {
      // Log the time from the event timeStamp until we called setState.
      const color = eventIsRepeat ? 'secondary-light' : 'warning';
      if (__DEV__ && debugTask) {
        debugTask.run(
          // $FlowFixMe[method-unbinding]
          console.timeStamp.bind(
            console,
            eventIsRepeat ? 'Consecutive' : 'Event: ' + eventType,
            eventTime,
            updateTime,
            currentTrack,
            LANES_TRACK_GROUP,
            color,
          ),
        );
      } else {
        console.timeStamp(
          eventIsRepeat ? 'Consecutive' : 'Event: ' + eventType,
          eventTime,
          updateTime,
          currentTrack,
          LANES_TRACK_GROUP,
          color,
        );