private static long getReplicationBarrier(Cell c) {
    return Bytes.toLong(c.getValueArray(), c.getValueOffset(), c.getValueLength());
  }
Helper class for storing replication barriers in family 'rep_barrier' of meta table.
<p/>
See SerialReplicationChecker on how to make use of the barriers.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/ReplicationBarrierFamilyFormat.java