We don't use rAF for scheduling anything anymore, yet we still enable it in ReactDOMFrameScheduling. It can probably be simplified a bit by not exposing it.
nextFrameTime = 8;
      }
      
      
      
      
      
      
      
      activeFrameTime = nextFrameTime < previousFrameTime
        ? previousFrameTime
        : nextFrameTime;
    } else {
      previousFrameTime = nextFrameTime;
    }
    frameDeadline = rafTime + activeFrameTime;
    if (!isIdleScheduled) {
      isIdleScheduled = true;
      window.postMessage(messageKey, '*');
    }
    var callback = scheduledRAFCallback;
    scheduledRAFCallback = null;
    if (callback) {
      callback(rafTime);
    }
  };
  rAF = function(callback: (time: number) => void): number {