public Void answer(InvocationOnMock invocation) {
        new Thread(() -> {
          Object[] args = invocation.getArguments();
          cpm.onResourcesAvailable((List<SamzaResource>) args[0]);
        }, "AMRMClientAsync").start();
        return null;
      }
Inject a duplicate request and check it is not accepted
samza-core/src/test/java/org/apache/samza/clustermanager/TestContainerPlacementActions.java