Getting error while listing metric (GCP) using filter using golang

Question

I am trying to list user defined log metrics in gcp using golang SDK.I am getting issue for the filter with prefix protoPayload.

req := &monitoringpb.ListMetricDescriptorsRequest{
        Name:      "projects/" + projectID,
        Filter:    "resource.type=\"gce_firewall_rule\" AND protoPayload.methodName=\"v1.compute.firewalls.patch\"", //OR protoPayload.methodName=\"v1.compute.firewalls.insert\"",
        PageSize:  0,
        PageToken: "",
    }
iter := c.ListMetricDescriptors(ctx, req)

    for {
        resp, err := iter.Next()
        if err == iterator.Done {
            break
        }
        Error("Gcp_CIS_rule_2_4", err)
        fmt.Println(resp)
    }

Error:= rpc error: code = InvalidArgument desc = Field filter had an invalid value of "resource.type="gce_firewall_rule" AND protoPayload.methodName="v1.compute.firewalls.patch"": The lefthand side of each expression must be prefixed with one of {group, metadata, metric, project, resource}.