code: function writeMessage(message, socket, signer) {
    var header = JSON.stringify(message.header);
    var parentHeader = JSON.stringify(message.parentHeader);
    var metadata = JSON.stringify(message.metadata);
    var content = JSON.stringify(message.content);
  
    var signature = signer.sign([ header, parentHeader, metadata, content ]);
  
    var socketData = [
      message.identities,
      '<IDS|MSG>',
      signature,
      header,
      parentHeader,
      metadata,
      content
    ];
    socket.send(socketData);
  }
docs: Helper to write out a message to as outgoing message data.