docs: public synchronized Channel findOrCreateChannel(ChannelData channelData) throws ChannelException {
          String channelName = channelData.getName();
          Channel rc = this.existingChannels.get(channelName);
          if (null == rc) {
              rc = createChannel(channelData);
              this.existingChannels.put(channelName, rc);
          }
          return rc;
      }