private static void Initialize()
 {
     appcenter_unity_distribute_set_delegate();
     del            = ReleaseAvailableFunc;
     willExitAppDel = WillExitAppFunc;
     noReleaseDel   = NoReleaseAvailableFunc;
     appcenter_unity_distribute_set_release_available_impl(del);
     appcenter_unity_distribute_set_no_release_available_impl(noReleaseDel);
     appcenter_unity_distribute_set_will_exit_app_impl(willExitAppDel);
 }
 private static extern void appcenter_unity_distribute_set_will_exit_app_impl(WillExitAppDelegate functionPtr);