How to set geo value use api.Nquad

I see the api.Value_GeoVal need a []bytes value

type Value_GeoVal struct {
	GeoVal []byte `protobuf:"bytes,7,opt,name=geo_val,json=geoVal,proto3,oneof" json:"geo_val,omitempty"`
}

but I don’t know how to set the value correctly.

I struggled with this too - I know this API is not super documented but some is just outright down to reading the code to figure out what you need to do…

Try putting the marshaled result of github.com/twpayne/go-geom/encoding/wkb in that field.