code: static SlicePredicate slicePredicateStartEndCol(byte[] startColName, byte[] endColName, int count) {
          if(startColName == null) startColName = EMPTY_BYTES;
          if(endColName == null) endColName = EMPTY_BYTES;
          SliceRange sliceRange =
              new SliceRange(ByteBuffer.wrap(startColName), ByteBuffer.wrap(endColName), false, count);
          SlicePredicate slicePred = new SlicePredicate();
          slicePred.setSlice_range(sliceRange);
          return slicePred;
      }
docs: Create a SlicePredicate that starts at the given column name, selecting up to
  {@link #MAX_COLS_BATCH_SIZE} columns.
  
  @param startColName  Starting column name as a byte[].
  @param endColName    Ending column name as a byte[]
  @return              SlicePredicate that starts at the given starting column name,
  ends at the given ending column name, selecting up to
  {@link #MAX_COLS_BATCH_SIZE} columns.