anchor.diff:                  [
                       {"text/plain", get_piqi_piq},
                       {"application/json", get_piqi_json},
  -                    {"application/protobuf", get_piqi_pb}
  +                    {"application/x-protobuf", get_piqi_pb}
                   ];
               'POST' ->
                   [
                       {"application/json", unused_value},
  -                    {"application/protobuf", unused_value},
  +                    {"application/x-protobuf", unused_value},
                       {"text/plain", unused_value}
                   ]
           end,
  
positive.code: %-define(DEBUG, 1).
  -include("debug.hrl").
  
  
  % XXX: or use "application/octet-stream" Content-Type instead of
  % "application/protobuf"?
  
  % XXX: set charset=UTF-8 in "Content-Type" response header for text (Piq), Json
  % and XML responses?
  
negative.code: % Utility functions
  %
  
  format_to_content_type('pb') -> "application/x-protobuf";
  format_to_content_type('json') -> "application/json";
  format_to_content_type('piq') -> "text/plain".
  
  
  content_type_to_format("application/x-protobuf") -> 'pb';
  content_type_to_format("application/json") -> 'json';
  content_type_to_format("text/plain") -> 'piq';
  content_type_to_format(_) -> 'undefined'.
  