 		} catch {
 			debugPrint("Error: \(error)")
 		}
-		return filesize
+		guard let size = filesize else {
+			return 0
+		}
+		return size
 	}
 	
 	//存储文件总长度.plist的文件路径

	}
	
	//文件已下载大小
	func fileDownloadSize(_ url: String) -> Int? {
		var filesize: Int?
		do {
			let attr = try FileManager.default.attributesOfItem(atPath: fileFullPath(url))

}

struct LQSessionModel {
	var stream: OutputStream?
	var url: String
	var totalLength: Int
	var progressBlock: (Int, Int, Double) -> Void
