NSURLSession

network requests are known as “tasks”
->
NSURLSessionTask
Data: into memory as NSData
Download:
Upload: specialized for uploading

Apple Documentation: URLSessionTask
https://developer.apple.com/documentation/foundation/urlsessiontask
Apple Documentation: URLSessionDataTask
Apple Documentation: URLSessionDownloadTask
Apple Documentation: URLSessionDelegate
Apple Documentation: URLSessionDataDelegate
Apple Documentation: URLSessionDownloadDelegate
Apple Documentation: URLSessionTaskDelegate

import UIKit

class ViewController: UIViewController {
	@IBOutlet weak var imageView: UIImageView!

	override func viewDidLoad(){
		super.viewDidLoad()

		let imageURL = NSURL(string: "https://upload.wikimedia.org/wikipedia/commons/4/4d/Cat_November_2010-1a.jpg");

		let task = NSURLSession.sharedSession().dataTaskWithURL(url: NSURL, completionHandler: (NSData?, NSURLResponse?, NSError?) -> Void)
	}
}

		if error == nil {
			let downloadedImage = UIImage(data: data!)
			self.imageView.image = downloadedImage
		}