anchor.diff:  
   -record(context, {
       rpc_mod,  % Piqi-RPC skeleton module generated by piqic-erlang-rpc
  -    impl_mod  % Piqi-RPC implementation module containing callback functions
  +    impl_mod,  % Piqi-RPC implementation module containing callback functions
  +
  +    request_body :: binary()  % body of a POST request
   }).
   
   
  
positive.code: % called for POST request
  known_content_type(ReqData, Context) ->
      ?PRINT(known_content_type),
      IsEmptyBody = (get_req_body(ReqData) =:= 'undefined'),
      IsKnownType =
          case wrq:get_req_header("content-type", ReqData) of
              "application/json" -> true;
              "application/xml" -> true;
              "application/x-protobuf" -> true;
              % allow content-type to be undefined when the body is empty
              'undefined' when IsEmptyBody -> true;
              _ -> false
          end,
      % otherwise, return 415 Unsupported media type
      {IsKnownType, ReqData, Context}.
  
  
  % Called for both GET and POST to find a match between provided content-types
  
negative.code: rpc(ReqData, Context, InputFormat) ->
      FuncName = list_to_binary(wrq:disp_path(ReqData)),
      ?PRINT({rpc, FuncName, InputFormat}),
  
      OutputFormat =
          case wrq:get_req_header("accept", ReqData) of
  