@Test
  public void testMax() throws InterruptedException, ExecutionException {
    assertEquals(COUNT - 1, AsyncAggregationClient
      .max(TABLE, new LongColumnInterpreter(), new Scan().addColumn(CF, CQ)).get().longValue());
  }
Same as TestAsyncAggregationClient, except that {@link AsyncTableImpl} is involved in addition to
{@link RawAsyncTableImpl}. Exercises the code paths in {@link AsyncTableImpl#coprocessorService}.
hbase-endpoint/src/test/java/org/apache/hadoop/hbase/client/TestAsyncAggregationClientWithCallbackThreadPool.java