@Override
    public void postCreateNamespace(ObserverContext<MasterCoprocessorEnvironment> ctx,
      NamespaceDescriptor desc) {
      postHookCalls.incrementAndGet();
    }
Tests class that validates that "post" observer hook methods are only invoked when the operation
was successful.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/procedure/TestMasterObserverPostCalls.java