code: public static int consumeLDQUOT(final Buffer buffer) throws SipParseException, IndexOutOfBoundsException,
              IOException {
          buffer.markReaderIndex();
          int consumed = consumeSWS(buffer);
          if (isNext(buffer, DQUOT)) {
              buffer.readByte();
              ++consumed;
          } else {
              buffer.resetReaderIndex();
              return 0;
          }
          return consumed;
      }
docs: Consume open double quotation mark (LDQUT), which according to RFC3261
  section 25.1 Basic Rules is:
  
  LDQUOT = SWS DQUOTE; open double quotation mark
  
  @param buffer
  @return true if we indeed did consume a LDQUOT
  @throws IOException
  @throws IndexOutOfBoundsException