This method shows a picker UI populated from the requesting player’s friend list and suggested friend list to send out game invites for titles using the Multiplayer Activity service.
async   _In_
Type: XAsyncBlock *A pointer to the XAsyncBlock that is passed to XAsyncRun.requestingUser   _In_
Type: XUserHandleA handle to the user that is sending the invites.
To send an invite with UI, after an activity is set using XblMultiplayerActivitySetActivityAsync (see example above), the title should call the XGameUiShowMultiplayerActivityGameInviteAsync API passing along the requesting user. It will use the current activity of the title and invite players using its connection string and settings.