docs: public static final long cheesyBufferCheckSum(ByteBuffer buffer) {
          final int mypos = buffer.position();
          buffer.position(0);
          long checksum = 0;
          if (buffer.hasArray()) {
              final byte bytes[] = buffer.array();
              final int end = buffer.arrayOffset() + mypos;
              for (int ii = buffer.arrayOffset(); ii < end; ii++) {
                  checksum += bytes[ii];
              }
          } else {
              for (int ii = 0; ii < mypos; ii++) {
                  checksum += buffer.get();
              }
          }
          buffer.position(mypos);
          return checksum;
      }