code: @SuppressWarnings("unused")
      final void handleReasonPhrase(ByteBuffer buffer, ResponseParseState state, HttpResponseBuilder builder) {
          StringBuilder stringBuilder = state.stringBuilder;
          while (buffer.hasRemaining()) {
              final char next = (char) buffer.get();
              if (next == '\n' || next == '\r') {
                  builder.setReasonPhrase(stringBuilder.toString());
                  state.state = ResponseParseState.AFTER_REASON_PHRASE;
                  state.stringBuilder.setLength(0);
                  state.parseState = 0;
                  state.leftOver = (byte) next;
                  state.pos = 0;
                  state.nextHeader = null;
                  return;
              } else {
                  stringBuilder.append(next);
              }
          }
      }
docs: Parses the reason phrase. This is called from the generated bytecode.
  
  @param buffer    The buffer
  @param state     The current state
  @param builder   The exchange builder
  @return The number of bytes remaining