How to trigger the ListSnapshot

I am trying to implement CSI driver to create the snapshot for volume. Now the driver is ok for create and delete the snapshot. I am trying to implement the
func (cs *ControllerServer) ListSnapshots(ctx context.Context, req *csi.ListSnapshotsRequest) (*csi.ListSnapshotsResponse, error)

Now the code is ready but I don’t know how to trigger this to list all the snapshots?

Cluster information:

Kubernetes version: 1.17
Cloud being used: (put bare-metal if not on a public cloud)
Installation method: kubeadm
Host OS:
CNI and version:
CRI and version: