CLGeocoder geocodeAddressString() hitting the limit - swift

Question

Im using MapKit's CLGeocoder().geocodeAddressString() to get the coordinates and county information for a list of addresses. Everything works great as long as the # of requests is under 50. but anything over 50 and im hitting API's limit. Since CLGeocoder calls are asynchronous, i can't easily throttle/control the flow of the calls (calling one address at a time, for instance). How would I do this correctly in the "asynchronous world"? (DISCLAIMER: I'm new to the world of GCD and asynchronous flow control, so I think I might require a more detailed response)
Here's the relevant code:
method of Class Property that calls CLGeocoder on the Property's Adress:
func initializeCoordinates() {
let addressForCoords = self.address.getAddress()
CLGeocoder().geocodeAddressString(addressForCoords, completionHandler: { (placemarks, error) -> Void in
if error != nil {
print(error!)
return
}
if placemarks!.count > 0 {
let placemark = placemarks?[0]
let location = placemark?.location
self.coordinates = location?.coordinate
if let subAdminArea = placemark?.subAdministrativeArea {
self.address.county = subAdminArea
}
}
})
}
and then in the section in the ImportVC that imports all the property's addresses from a textBox (and makes the call to initializeCoordinates method on each Property:
for line in importText {
let newAddress = Address()
let newHouse = Property()
// parse the tab delimited address for each line of input
let address = line.components(separatedBy: "\t")
if address.count == 4 {
newAddress.street = address[0]
newAddress.city = address[1]
newAddress.state = trimState(state: address[2])
newAddress.zip = address[3]
newHouse.address = newAddress
newHouse.initializeCoordinates()
houses.append(newHouse)
}
}

Answer 1

I faced a similar problem recently. Replace your for-loop with a recursive function that calls itself at the end. However the trick is to call its self with a 0.2 second delay. I use 0.4 to be on the safe side. This will increase the waiting time for the user, although we have no choice due to the API limit.