code: func newIngressNetwork() *api.Network {
  	return &api.Network{
  		ID: identity.NewID(),
  		Spec: api.NetworkSpec{
  			Ingress: true,
  			Annotations: api.Annotations{
  				Name: "ingress",
  			},
  			DriverConfig: &api.Driver{},
  			IPAM: &api.IPAMOptions{
  				Driver: &api.Driver{},
  				Configs: []*api.IPAMConfig{
  					{
  						Subnet: "10.255.0.0/16",
  					},
  				},
  			},
  		},
  	}
  }
docs: // newIngressNetwork returns the network object for the default ingress
  // network, the network which provides the routing mesh. Caller will save to
  // store this object once, at fresh cluster creation. It is expected to
  // call this function inside a store update transaction.