@Override
  public void preCreateTable(ObserverContext<MasterCoprocessorEnvironment> ctx,
    TableDescriptor desc, RegionInfo[] regions) throws IOException {
    // we rely on the fact that there is only 1 instance of our MasterObserver. We keep track of
    // when the operation starts before the operation is executing.
    this.createTableStartTime = EnvironmentEdgeManager.currentTime();
  }
Returns the max memory of the process. We will use this to define a gauge metric
hbase-examples/src/main/java/org/apache/hadoop/hbase/coprocessor/example/ExampleMasterObserverWithMetrics.java