@Override
    public ByteBuffer getCommBuffer() {
      return null;
    }
A fake factory which returns a list of connections. Fake connections are created by calling
addConnection or add error. The factory maintains a queue of connections which will be handed
out when the queue manager calls createClientToServerConnection. If an error was added, the
factory will return null instead.
geode-core/src/integrationTest/java/org/apache/geode/cache/client/internal/QueueManagerIntegrationTest.java