code: func (e *Engine) Accept(server transport.Server) {
  	e.tomb.Go(func() error {
  		for {
  			// return if dying
  			if !e.tomb.Alive() {
  				return tomb.ErrDying
  			}
  
  			// accept next connection
  			conn, err := server.Accept()
  			if err != nil {
  				// call error callback if available
  				if e.OnError != nil {
  					e.OnError(err)
  				}
  
  				return err
  			}
  
  			// handle connection
  			if !e.Handle(conn) {
  				return nil
  			}
  		}
  	})
  }
docs: // Accept begins accepting connections from the passed server.