[Syncing multiple async tasks in Swift - code snippets 1]

performNetworkRequest.swift

func performNetworkRequest(url: String,
                           completion: @escaping (Data?, Error?) -> Void) {
	// create a url
    let requestUrl = URL(string: url)
    
    // create a data task
    let task = URLSession.shared.dataTask(with: requestUrl!) { (data, response, error) in
        completion(data, error)
    }
    task.resume()
}