@Override
    protected void encodeThis(ByteBuffer buffer) {
        super.encodeThis(buffer); // takes care of index bytes
        // TODO: use a better format for encoding the location on the wire.
        putString(location.backendString(), buffer);
    }
Construct from a Location and a field name.
The Location must be a geo circle.
If the Location has an attribute set, it must match the field name.
container-search/src/main/java/com/yahoo/prelude/query/GeoLocationItem.java