anchor.diff:                _state = _State.HEADER_VALUE_FOLDING_OR_ENDING;
               } else if (byte != _CharCode.SP && byte != _CharCode.HT) {
                 // Start of new header value.
  -              _headerValue.addCharCode(byte);
  +              _headerValue.add(byte);
                 _state = _State.HEADER_VALUE;
               }
               break;
  
positive.code:               if (byte == _CharCode.CR || byte == _CharCode.LF) {
                  throw new HttpParserException("Invalid request URI");
                }
                _uri_or_reason_phrase.addCharCode(byte);
              }
              break;
  
  
negative.code:               _state = _State.HEADER_ENDING;
              } else {
                // Start of new header field.
                _headerField.add(_toLowerCase(byte));
                _state = _State.HEADER_FIELD;
              }
              break;
  