public static boolean matchingFamily(final Cell left, final byte[] buf) {
    if (buf == null) {
      return left.getFamilyLength() == 0;
    }
    return PrivateCellUtil.matchingFamily(left, buf, 0, buf.length);
  }
Flatten the map of cells out under the CellScanner
@param map Map of Cell Lists; for example, the map of families to Cells that is used inside
           Put, etc., keeping Cells organized by family.
@return CellScanner interface over <code>cellIterable</code>
hbase-common/src/main/java/org/apache/hadoop/hbase/CellUtil.java