升级iOS10之后之前打电话的UI弹出总是有2S延迟，因为openURL在ios10及其之后会阻塞主线程，开个子线程就OK。
NSString *callPhone = [NSString stringWithFormat:@"telprompt://%@", phoneNO];
dispatch_async(dispatch_get_global_queue(0, 0), ^{
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:callPhone]];
});
