@Override
      public boolean evaluate() throws Exception {
        List<ReplicationLoadSource> list =
          hbaseAdmin.getClusterMetrics(EnumSet.of(Option.LIVE_SERVERS)).getLiveServerMetrics()
            .get(serverName).getReplicationLoadSourceList();
        return list.size() > greaterThan;
      }
Wait until Master shows metrics counts for ReplicationLoadSourceList that are greater than
<code>greaterThan</code> for <code>serverName</code> before returning. We want to avoid case
where RS hasn't yet updated Master before allowing test proceed.
@param greaterThan size of replicationLoadSourceList must be greater before we proceed
hbase-server/src/test/java/org/apache/hadoop/hbase/replication/TestReplicationStatus.java