See #17798
bundleType: BundleType,
  
  overrideHookState?: ?(
    fiber: Object,
    id: number,
    path: Array<string | number>,
    value: any,
  ) => void,
  
  overrideProps?: ?(
    fiber: Object,
    path: Array<string | number>,
    value: any,
  ) => void,
  
  scheduleUpdate?: ?(fiber: Object) => void,
  setSuspenseHandler?: ?(shouldSuspend: (fiber: Object) => boolean) => void,
  
  currentDispatcherRef?: {|current: null | Dispatcher|},
  
  
  getCurrentFiber?: () => Fiber | null,
  
  ComponentTree?: any,
  
  Mount?: any,
  ...
};
export type ChangeDescription = {|
  context: Array<string> | boolean | null,