code: @Override
      public final Buffer readUntilSingleCRLF() throws IOException {
          final int start = getReaderIndex();
          int found = 0;
          while (found < 2 && hasReadableBytes()) {
              final byte b = readByte();
              if (found == 0 && b == CR) {
                  ++found;
              } else if (found == 1 && b == LF) {
                  ++found;
              } else {
                  found = 0;
              }
          }
          if (found == 2) {
              return slice(start, getReaderIndex() - 2);
          } else {
              setReaderIndex(start);
              return null;
          }
      }
docs: {@inheritDoc}