code: public DRow getRow(String storeName, String rowKey) {
          return new DRow(m_tenant, storeName, rowKey);
      }
docs: Get iterator for rows with a specific set of keys. Results are returned as an
  Iterator of {@link DRow} objects. If any given row is not found, no entry
  with its key will be returned.
  
  @param storeName Name of store to query.
  @param rowKeys   Collection of row keys to read.
  @return          Iterator of {@link DRow} objects. May be empty but not null.