code: func server(c context.Context) crimson.CrimsonServer {
  	s, _ := c.Value(&serverKey).(crimson.CrimsonServer)
  	if s == nil {
  		panic("impossible, &serverKey is not set")
  	}
  	return s
  }
docs: // server returns crimson.CrimsonServer as passed to InstallHandlers.
  //
  // It is used to pull all data necessary to render pages.