. NSData, , plist. NSKeyedArchiver, , NSCoding, NSData.
DownloadObject *object = [[DownloadObject alloc]initWithKey:number name:@"hey" progress:number size:number path:@"hey" progressBytes:number];
NSData* objData = [NSKeyedArchiver archivedDataWithRootObject:object];
[downloadArray addObject:objData];
[object release];
NSData, NSKeyedUnarchiver:
NSData* objData = [downloadArray objectAtIndex:0];
DownloadObject* object = [NSKeyedUnarchiver unarchiveObjectWithData:objData];
. -initWithCoder: ivars, ivars :
key = [[coder decodeObjectForKey:@"Key"] copy];
-retain, , copy, , 2 . , init.
, , downloadArray, -alloc, -retain , 2. Objective-C .