code: func (m *InjectableEndpoint) MTU() uint32 {
  	minMTU := ^uint32(0)
  	for _, endpoint := range m.routes {
  		if endpointMTU := endpoint.MTU(); endpointMTU < minMTU {
  			minMTU = endpointMTU
  		}
  	}
  	return minMTU
  }
docs: // MTU implements stack.LinkEndpoint.