How to use NSOutputStream's outputStreamToFileAtPath

outputStreamToFileAtPathDemo.m

- (void)outputStreamToFileAtPathDemo
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *file = [documentsDirectory stringByAppendingPathComponent:@"foo.dat"];
    NSLog(@"file: %@", file);
    
    NSOutputStream *output = [NSOutputStream outputStreamToFileAtPath:file append:NO];
    [output open];
    
    //
    //...
    //

    [output close];
}