code: function ServiceNode(host, port, addresses, metadata) {
  	this.host = host;
  	this.port = port;
  	this.addresses = addresses;
  	this.data = metadata || {};
  }
docs: This the representation of a node on the discovery network
  
  @param {string}   host       The hostname for the node
  @param {number}   port       The port on which the service is reachable
  @param {string[]} addresses  A list of ips on which the service is reachable
  @param {Object}   [metadata] The metadata announced by the service
  @constructor