code: @Override public long skip(long n) throws IOException {
          abortIfNeeded();
          int available = max_pos - curr_pos;
          if (n > available)
              n = available;
          if (n < 0)
              return 0;
          curr_pos += n;
          return n;
      }
docs: {@inheritDoc}
  <p>
  Note: This implementation will only skip up to the end of the buffered
  data, potentially skipping 0 bytes.