public String waitOnRegionServer(final int serverNumber) {
    return this.hbaseCluster.waitOnRegionServer(serverNumber);
  }
Wait for the specified region server to stop. Removes this thread from list of running threads.
@return Name of region server that just went down.
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/MiniHBaseCluster.java