I want to invoke Webview.loadRequest() multiple times in Swift3 - ios

Question

I am new to IOS development. And I am working to get page load time of web on IOS emulators.
Since, I am targeting top 100 alexa websites, it would be difficult to load each url and record time for load. So, I am planning to automate it.
Below is my code:
import UIKit
class ViewController: UIViewController, UIWebViewDelegate{
var startTime = Date()
#IBOutlet weak var WebView: UIWebView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
// let URL = Foundation.URL(string: "http://www.youtube.com")
startTime = Date()
print(startTime)
for url in returnURLArray(){
WebView.delegate = self
WebView.loadRequest(URLRequest(url: URL(string: url)!))
print("I am trying to load...."+url)
sleep(100)
print("back to execute other urls")
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func webViewDidFinishLoad(_ WebView: UIWebView)
{
//Check here if still webview is loding the content
if (WebView.isLoading){
print("I am loading now...")
return;
}
//after code when webview finishes
let finishTime = Date()
print(finishTime.timeIntervalSince(startTime))
NSLog("Webview loding finished")
}
func returnURLArray() -> [String] {
let file = "topalexawebsites.txt" //this is the file. we will write to and read from it
var text2 = String()
var urlArr = [String]()
if let dir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first {
let path = dir.appendingPathComponent(file)
do{
print(path)
text2 = try String(contentsOf: path, encoding: String.Encoding.utf8).trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
urlArr = text2.components(separatedBy: "\n")
// print(text2)
// for urls in urlArr{
// print(urls)
//}
}
catch let err as NSError{
print(err)
}
}
return urlArr
}
}
I want to execute all urls one by one in my topalexawebsites.txt and record load time for it.
But, here I am seeing only one cycle is working, and since urls are in a loop, only the also one gets loaded.