An idea for maintaining orientation state through notify_state

UIOrientationPortableState.h

union UIOrientationPortableState {
    struct UIOrientationState {
        enum UIOrientation { /* this is UIInterfaceOrientation, but unsigned */
            UIOrientationUnknown,
            UIOrientationPortrait,
            UIOrientationPortraitUpsideDown,
            UIOrientationLandscapeRight,
            UIOrientationLandscapeLeft
        }
        current  : 3, // may be the orientation the device is transitioning to, if transition != UITransitionPhaseZero
        previous : 3; // may be unknown when transition == UITransitionPhaseZero
        enum UIAnimationCurve { /* this is UIViewAnimationCurve, but unsigned */
            UIAnimationCurveEaseInOut,
            UIAnimationCurveEaseIn,
            UIAnimationCurveEaseOut,
            UIAnimationCurveLinear
        } curve : 2; // describes the calculation used for the transition between current and previous
        enum UITransitionPhase {
            UITransitionPhaseZero, // transition is not is progress
            /* transition in progress */
            UITransitionPhaseDone = ((1 << 24) - 1)
        } transition : 24; // use floating division with UITransitionPhaseDone to get the percent into the transition
        float duration; // total duration of the transition in seconds
    } state;
    uint64_t hash;
};