HRESULT XGameUiShowMessageDialogAsync(  
         XAsyncBlock* async,  
         const char* titleText,  
         const char* contentText,  
         const char* firstButtonText,  
         const char* secondButtonText,  
         const char* thirdButtonText,  
         XGameUiMessageDialogButton defaultButton,  
         XGameUiMessageDialogButton cancelButton  
)  

if (FAILED(XGameRuntimeInitialize()))  
    return 1;

XTaskQueueHandle queue;
DX::ThrowIfFailed(
    XTaskQueueCreate(XTaskQueueDispatchMode::ThreadPool, XTaskQueueDispatchMode::Immediate, &queue)  
);

XAsyncBlock* ab = new XAsyncBlock;
ZeroMemory(ab, sizeof(XAsyncBlock));
ab->queue = queue;

// show dialog, wait for completion, get result.

XGameUiMessageDialogButton button;
if (SUCCEEDED(XGameUiShowMessageDialogAsync(ab, u8"Title String", u8"This is content text",
                                            u8"Option #1", u8"Option #2", u8"Option #3",
                                            XGameUiMessageDialogButton::First,
                                            XGameUiMessageDialogButton::Third)) &&
    SUCCEEDED(XAsyncGetStatus(ab, true)) &&
    SUCCEEDED(XGameUiShowMessageDialogResult(ab, &button)))  
{
    DoSomethingWithResponse(button);  // set breakpoint here to investigate
}