@Override
    public Double dist(V firstMember, V secondMember, GeoUnit geoUnit) {
        return get(distAsync(firstMember, secondMember, geoUnit));
    }
@Test
    public void testDistEmpty() {
        RGeo<String> geo = redisson.getGeo("test");
        
        assertThat(geo.dist("Palermo", "Catania", GeoUnit.METERS)).isNull();
    }