@Override
  public void preDisableTable(ObserverContext<MasterCoprocessorEnvironment> ctx,
    TableName tableName) throws IOException {
    // Increment the Counter for disable table operations
    this.disableTableCounter.increment();
  }
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