docs: private IChannelConsumer getClientChannelForSubscription(
              String functionalityName,
              IAsyncMessageClient client) throws ServiceGroundingException
      {
          if (null != this.subscriptionsConsumerChannel)
          {
              return this.subscriptionsConsumerChannel;
          }
  
          this.subscriptionsConsumerChannel = createClientSubscriptionChannelFor(functionalityName);
          this.subscriptionsConsumerChannel.addClientCallback(client);
          return this.subscriptionsConsumerChannel;
      }