fix gif caching

Pocket Poster/Packages/GIFImage/Sources/extension/CGImageSource+GIFImage.swift

@@ -0,0 +1,39 @@
+//
+//  File.swift
+//  
+//
+//  Created by Igor Ferreira on 05/04/2022.
+//
+
+import Foundation
+import ImageIO
+
+extension CGImageSource {
+    func intervalAtIndex(_ index: Int) -> TimeInterval? {
+        guard let properties = CGImageSourceCopyPropertiesAtIndex(self, index, nil) else {
+            return nil
+        }
+
+        guard let gifProperties = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary.asKey) else {
+            return nil
+        }
+
+        let dictionary = unsafeBitCast(gifProperties, to: CFDictionary.self)
+
+        let pointer: UnsafeRawPointer
+        if let delay = CFDictionaryGetValue(dictionary, kCGImagePropertyGIFDelayTime.asKey) {
+            pointer = delay
+        } else if let unclampedDelay = CFDictionaryGetValue(dictionary, kCGImagePropertyGIFUnclampedDelayTime.asKey) {
+            pointer = unclampedDelay
+        } else {
+            return nil
+        }
+
+        let interval = unsafeBitCast(pointer, to: AnyObject.self).doubleValue ?? 0.0
+        if interval > 0.0 {
+            return interval
+        } else {
+            return nil
+        }
+    }
+}