code: public long next() {
          try {
              ByteBufferUtil.readWithShortLength(input);
  
              final long offset = input.readLong();
  
              // TODO: Because this is version ic > ia promotedIndex is true and we need to handle it. See C* Descriptor
              skipPromotedIndex(input);
  
              return offset;
          } catch (IOException e) {
              throw new IOError(e);
          }
      }
docs: Get the next offset from the SSTable index.
  @return SSTable offset.