code: function ServiceFactory(prefix, etcd) {
    if (!(this instanceof ServiceFactory)) {
      return new ServiceFactory(prefix, etcd);
    }
  
    if (!etcd) { throw new Error('A valid Etcd instance is required.'); }
  
    this.etcd = etcd;
    this.prefix = prefix || 'discover';
  }
docs: /*
  # ServiceFactory
  Factory for producing properly configured `Service` objects within the context of this
  configured instance.
  
  + prefix (string, 'discover') ... String representing the prefix where `Discover` is registerd.
  + etcd (Etcd) ... Configured instance of `node-etcd`