docs: public Set<String> getChannelNames() {
          Set<String> ret = Collections.EMPTY_SET;
  
          JsonObject channels = getJsonObject(jsonConfig, "channels");
          if (channels != null) {
              final Set<String> channelNames = channels.keySet();
              if (channelNames != null && !channelNames.isEmpty()) {
                  ret = new HashSet<>(channelNames);
              }
          }
          return ret;
      }