code: function setServer(msg, done) {
    var seneca = this
    var context = msg.context || locals.context
    var adapter = msg.adapter || locals.adapter
    var options = msg.options || locals.options
    var auth = msg.auth || locals.auth
    var routes = msg.routes
  
    // If the adapter is a string, we look up the
    // adapters collection in opts.adapters.
    if (!_.isFunction(adapter)) {
      return done(new Error('Provide a function as adapter'))
    }
  
    // either replaced or the same. Regardless
    // this sets what is called by mapRoutes.
    locals = {
      context: context,
      adapter: adapter,
      auth: auth,
      options: options
    }
  
    // If we have routes in the msg map them and
    // let the matter handle the callback
    if (routes) {
      mapRoutes.call(seneca, { routes: routes }, done)
    } else {
      // no routes to process, let the
      // caller know everything went ok.
      done(null, { ok: true })
    }
  }
docs: Sets the 'default' server context. Any call to mapRoutes will use this server as it's context if none is provided. This is the server returned by getServer.