anchor.diff:  param_error({type, Value}, Name) ->
       param_error_(Name, #{error => wrong_type, data => Value});
   param_error({body, Value}, Name) ->
  -    param_error_(Name, #{error => invalid_body, data => Value}).
  +    param_error_(Name, #{error => invalid_body, data => Value});
  +param_error({body_too_big, Value}, Name) ->
  +    param_error_(Name, #{error => body_too_big, data => Value}).
   
   param_error_(Name, Info) ->
       {error, {validation_error, to_binary(Name), Info}}.
  
positive.code:     end.
  
  get_param_value("body", _, Req0) ->
      case cowboy_req:read_body(Req0) of
          {ok, <<>>, Req} -> {ok, <<>>, Req};
          {ok, Body, Req} ->
              try
  
negative.code:               error:_ ->
                  {error, Reason} = param_error({body, Body}, <<>>),
                  {error, Reason, Req}
              end;
          {more, Body, Req} ->
              {error, Reason} = param_error({body_too_big, Body}, <<>>),
              {error, Reason, Req}
      end;
  get_param_value("query", Name, Req) ->
      QS = cowboy_req:parse_qs(Req),
  