anchor.diff:          | OnExiting of (Browser.HTMLElement -> unit)
           | OnExited of (Browser.HTMLElement -> unit)
           | Children of U2<React.ReactNode, (TransitionStatus -> React.ReactNode)>
  +        | Class of string
           | Ref of (obj -> obj)
           | Key of string
           static member Custom(key: string, value: obj): TransitionProps =
  
positive.code:         exitDone: string option
      }
  
      type CSSTransitionProps =
          | In of bool
          | Appear of bool
  
negative.code:         | [<CompiledName("exited")>] Exited
          | [<CompiledName("unmounted")>] Unmounted
  
      [<RequireQualifiedAccess>]
      type TransitionProps =
          | In of bool
          | Appear of bool
  