@Override
    public void preStopRegionServer(ObserverContext<RegionServerCoprocessorEnvironment> env)
      throws IOException {
      abortCount.incrementAndGet();
      if (!stopAllowed) {
        throw new IOException("Stop not allowed");
      }
    }
Tests that only a single abort is processed when multiple aborts are requested.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRegionServerAbort.java