Loading Indicator in Status Bar iOS

I think what you are looking for is:

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

Swift 3

UIApplication.shared.isNetworkActivityIndicatorVisible = true

as doc'd here: https://developer.apple.com/documentation/uikit/uiapplication/1623102-isnetworkactivityindicatorvisibl

Same as above just in Swift:

UIApplication.sharedApplication().networkActivityIndicatorVisible = true