private static Observable<Address> addressesToObservable(final List<Address> addresses) {
        return CollectionUtils.isEmpty(addresses) ?
                Observable.error(new RuntimeException("no result from Android geocoder")) :
                Observable.fromIterable(addresses);
    }
Retrieve the physical address for coordinates. The work happens on the network scheduler.

@param coords the coordinates
@return a single containing one location or an error
main/src/main/java/cgeo/geocaching/address/AndroidGeocoder.java