anchor.diff:      // 'T -> M<'T>
       member __.Return value
           : ReaderStateFunc<'Env, 'State, 'T> =
  -        fun env state ->
  +        fun _ state ->
           value, state
   
       // M<'T> -> M<'T>
  
positive.code:     // 'T -> M<'T>
      member __.Return value
          : ReaderProtectedStateFunc<'Env, 'State, 'T, 'Error> =
          fun env state ->
          Choice1Of2 (value, state)
  
      // M<'T> -> M<'T>
  
negative.code: /// <typeparam name="Error"></typeparam>
  type StatefulChoiceFunc<'State, 'T, 'Error> =
      'State -> Choice<'T, 'Error> * 'State
  
  /// <summary>
  /// </summary>
  /// <typeparam name="State"></typeparam>
  /// <typeparam name="T"></typeparam>
  type AsyncStateFunc<'State, 'T> =
      'State -> Async<'T * 'State>
  
  /// <summary>
  /// </summary>
  /// <typeparam name="State"></typeparam>
  /// <typeparam name="T"></typeparam>
  /// <typeparam name="Error"></typeparam>
  type AsyncProtectedStateFunc<'State, 'T, 'Error> =
      'State -> Async<Choice<'T * 'State, 'Error>>
  
  
  (*** Workflow Builders ***)
  