anchor.diff:  
   %% @doc Decodes a operation name from a PB message into an atom.
   -spec decode_flag_op(atom()) -> atom().
  +
   decode_flag_op('ENABLE')  -> enable;
   decode_flag_op('DISABLE') -> disable.
   
  
positive.code: encode_map_entry({{Name, register=Type}, Value}, _Mods) when is_binary(Value) ->
      #mapentry{field=encode_map_field({Name, Type}), register_value=Value};
  encode_map_entry({{Name, flag=Type}, Value}, _Mods) when is_boolean(Value) ->
      #mapentry{field=encode_map_field({Name, Type}), flag_value=Value};
  encode_map_entry({{Name, map=Type}, Value}, Mods) when is_list(Value) ->
      #mapentry{field=encode_map_field({Name, Type}),
                map_value=[ encode_map_entry(Entry, Mods) || Entry <- Value ]};
  
negative.code: encode_type(register) -> 'REGISTER';
  encode_type(flag)     -> 'FLAG';
  encode_type(map)      -> 'MAP'.
  
  %% @doc Encodes a flag value into its PB message equivalent.
  encode_flag_value(on) -> true;
  encode_flag_value(off) -> false;
  encode_flag_value(Other) -> Other.
  
  %% ========================
  %% FETCH REQUEST / RESPONSE
  