Как правильно использовать расчет расстояний Distance Matrix API?

private LocationRequest initLocationRequest() {
        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(LOCATION_INTERVAL_SECONDS);
        mLocationRequest.setFastestInterval(LOCATION_INTERVAL_SECONDS / 2);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        return mLocationRequest;
    }

    private void setLocationUpdates() {
        mLocationCallback = new LocationCallback() {
            @Override
            public void onLocationResult(LocationResult locationResult) {
                for (Location location : locationResult.getLocations()) { 
                  saveInDb(location );
                }
            }
        };

        initLocationRequest();
        mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, null);
    }