ScreenCaptureKit: SCShareableContent getShareableContentExcludingDesktopWindows never calls completion handler

Question

I am trying to capture a window image using ScreenCaptureKit. It works fine in swift, but I need to use objective-c, and it never calls the completion handler when getting a SCSharableContent. Is there something obvious I've been missing for the last two days?

@import Foundation;
@import CoreServices;
@import to use ;

BOOL CanCapture(void) {
    for(;;) {
        if (CGPreflightScreenCaptureAccess()) {
            return true;
        }
        if (!CGRequestScreenCaptureAccess()) {
            return false;
        }
    }
    return false;
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        if (CanCapture()) {
            NSLog(@"Here\n");
            [SCShareableContent getShareableContentExcludingDesktopWindows: true
                                                       onScreenWindowsOnly: true
                                                         completionHandler: ^(SCShareableContent *shareableContent, NSError *error) {
                NSLog(@"But not Here\n");
            }];
        }
    }
}