code: private Message prepare(String channel, Message message, Recipient[] recipients) {
          message.setMetadata("cwf.pub.node", nodeId);
          message.setMetadata("cwf.pub.channel", channel);
          message.setMetadata("cwf.pub.event", UUID.randomUUID().toString());
          message.setMetadata("cwf.pub.when", System.currentTimeMillis());
          message.setMetadata("cwf.pub.recipients", recipients);
          return message;
      }
docs: Adds publication-specific metadata to the message.
  
  @param channel The message channel.
  @param message The message.
  @param recipients The message recipients.
  @return The original message.