ArgumentNullException thrown when address is empty

[stefankip]

I'm using the Google geocoder and want to lookup a country.
The documentation states that this is possible by only supplying a components parameter.
But if I supply an empty string to the GeocodeAsync method, I get a ArgumentNullException:
https://github.com/chadly/Geocoding.net/blob/master/src/Geocoding.Google/GoogleGeocoder.cs#L131