code: private Iterator<String> decodeKeys(final Iterator<Row<ByteBuffer, DeltaKey>> iter) {
          return new AbstractIterator<String>() {
              @Override
              protected String computeNext() {
                  while (iter.hasNext()) {
                      Row<ByteBuffer, DeltaKey> row = iter.next();
                      if (!row.getColumns().isEmpty()) { // Ignore range ghosts
                          return AstyanaxStorage.getContentKey(row.getRawKey());
                      }
                  }
                  return endOfData();
              }
          };
      }
docs: Decodes row keys returned by scanning a table.