code: public ByteBuffer byteBuffer(DecoratedKey partitionKey, CellName cellName) {
          return type.builder().add(partitionKey.getKey()).add(cellName.toByteBuffer()).build();
      }
docs: Returns the {@link ByteBuffer} representation of the full row key formed by the specified partition key and the
  clustering key.
  
  @param partitionKey A partition key.
  @param cellName     A clustering key.
  @return The {@link ByteBuffer} representation of the full row key formed by the specified key pair.