         objc_sync_enter(self)
         defer { objc_sync_exit(self) }
         
-        self.requestIDs.removeAll()
+        self.requests.removeAll()
     }
     
     private func makeCancelledError() -> Error {

                                   userInfo: [NSLocalizedDescriptionKey : "Failed to fetch AVAsset."]))
            }
        }
        self.add(requestID: requestID)
    }
    
    private func waitForExportToFinish(exportSession: AVAssetExportSession, group: DispatchGroup, progress: (Double) -> Void) {

                    progress(p)
                }
                
                asset.fetchImageData(options: options, completeBlock: { (data, info) in
                    DKImageAssetExporter.ioQueue.async {
                        if var imageData = data {
                            if let info = info, let fileURL = info["PHImageFileURLKey"] as? NSURL {
                                asset.fileName = fileURL.lastPathComponent
                            } else {
                                asset.fileName = asset.localIdentifier
                            }
                            
                            if FileManager.default.fileExists(atPath: asset.localTemporaryPath!.path) {
