Get Distance between two points Swift 5 - swift

Question

I'm trying to get the distance between tow points, current location, and another point.
All the data is calculate great, but I can't get the value to asign it to the object, and then create the table.
The distance is created later than the object even I hace make an async queue.
I can't find the problem maybe I'm too new in this.
Thanks for the help
DispatchQueue.global(qos: .utility).async {
for snap in snapshot.children {
let postSnap = snap as! DataSnapshot
if let dict = postSnap.value as? [String:AnyObject] {
let farcoordenadas = dict["coordenadas"] as! [Double]
let lat = (farcoordenadas[0] as! Double)
let long = (farcoordenadas[1] as! Double)
let location = CLLocationCoordinate2D(latitude: lat, longitude: long)
let farcalle = (dict["calle"] as! String)
let fartelefono = (dict["telefono"] as! String)
let farpoblacion = (dict["poblacion"] as! String)
let farhorario = (dict["horario"] as! String)
let request = MKDirections.Request()
request.source = MKMapItem(placemark: MKPlacemark(coordinate:self.userLocation!))
request.destination = MKMapItem(placemark: MKPlacemark(coordinate: location))
request.transportType = .automobile
let directions = MKDirections(request: request)
directions.calculate { (response, error) -> Void in
if let response = response, let route = response.routes.first {
print(route.distance)
//converts from meters to miles
var routeDistance = route.distance/1000
//formats the string to two decimals.
distancia = String(format: "%.0f" , routeDistance)
}
return
}
DispatchQueue.main.async {
let farmaciapueblo = Farmacia(fecha:dateString, horario:farhorario, poblacion: farpoblacion, telefono:fartelefono, calle:farcalle, coordenadas:farcoordenadas, distancia:distancia)
self.farmaciasrural.append(farmaciapueblo)
self.farmaciasrural.sort(by: myLocation) // mutating version
self.activityIndicator.stopAnimating()
self.tableView.reloadData()
}
}
}
}