docs: public int readUnsignedShort(final int offset) throws IOException {
          final int bytesToRead = Math.max(0, offset + 2 - used);
          if (bytesToRead > 0) {
              readMore(bytesToRead);
          }
          return ((buf[offset] & 0xff) << 8) //
                  | (buf[offset + 1] & 0xff);
      }