@Test
  public void testClose() {
    manager = new ConnectionManagerImpl("pool", factory, endpointManager, 10, 0, -1, -1, logger,
        60 * 1000, cancelCriterion, poolStats);
    manager.start(background);

    Connection connection = manager.borrowConnection(0);

    manager.borrowConnection(0);
    manager.returnConnection(connection);

    assertThat(factory.creates.get()).isEqualTo(2);
    assertThat(factory.destroys.get()).isEqualTo(0);

    manager.close(false);

    assertThat(factory.closes.get()).isEqualTo(2);
    assertThat(factory.destroys.get()).isEqualTo(2);
  }
Test borrow connection toward specific server (use). Max connection is 5, and there is no free
connections in pool.
We are waiting for returnConnection for connection toward this specific server.
After it is returned, we will reuse it.
geode-core/src/integrationTest/java/org/apache/geode/cache/client/internal/pooling/ConnectionManagerJUnitTest.java