code: @Override
      public int compareTo(CharSlice o) {
          if (o.off != off) {
              return Integer.compare(off, o.off);
          }
          return Integer.compare(o.len, len);
      }
docs: Compare slice with other slice.
  
  Slice ordering:
  - Firstly ordered by start (offset) position.
  - Secondly ordered by reverse length (longest slice first).
  
  Result is undefined of the two slices point to different byte buffers.
  
  @param o The other slice.
  @return Compared value.