https://mongodb.github.io/mongo-csharp-driver/2.12/apidocs/html/M_MongoDB_Driver_GeoNearPoint_op_Implicit_1.htm
GeoNearPoint Implicit Conversion (GeoJsonPoint(GeoJson2DGeographicCoordinates) to GeoNearPoint)
Implicit conversion to wrap a 2D GeoJson point in a GeoNearPoint value.
implicit conversion