@Test(expected = ExecutionException.class)
 public void testPutAsyncOperationThrowsExceptionWhenQuorumSizeNotMet() throws Exception {
   Future<Void> foo = cache4.putAsync(1, "");
   foo.get();
 }
 @Test
 public void testPutAsyncOperationSuccessfulWhenQuorumSizeMet() throws Exception {
   Future<Void> foo = cache1.putAsync(1, "");
   foo.get();
 }