Add Async image loading

Examples/Async image loading/RemoteImage/ImageCache.swift

@@ -0,0 +1,27 @@
+//
+//  File 2.swift
+//  
+//
+//  Created by Callum Trounce on 05/06/2019.
+//
+
+import Foundation
+import SwiftUI
+
+@available(iOS 13.0, *)
+class ImageCache {
+    
+    private let cache = NSCache<NSURL, CGImage>()
+    
+    private let queue = DispatchQueue.init(label: "cacheQueue", qos: .userInteractive)
+    
+    func store(image: CGImage, for url: URL) {
+        queue.async { [unowned cache] in
+            cache.setObject(image, forKey: url as NSURL)
+        }
+    }
+    
+    func image(for url: URL) -> CGImage? {
+        return cache.object(forKey: url as NSURL)
+    }
+}