@Test
  public void testRequestInfoNullInResponse() throws Exception {
    NetworkClient compositeClient = factory.getNetworkClient();
    when(diskMocks.client.sendAndPoll(any(), any(), anyInt())).thenReturn(
        Collections.singletonList(new ResponseInfo(null, NetworkClientErrorCode.NetworkError, null)));
    compositeClient.sendAndPoll(Collections.emptyList(), Collections.emptySet(), 1000);
    verify(diskMocks.client).sendAndPoll(Collections.emptyList(), Collections.emptySet(), 1000);
  }
No NPEs should happen if a child client returns {@link ResponseInfo} with a null {@link RequestInfo}. This is used
in by client implementations to indicate a connection creation failure so that the failure can be tracked.
@throws Exception
ambry-network/src/test/java/com/github/ambry/network/CompositeNetworkClientTest.java