_KI_CALLBACK

Windows 10 2004 (May 2020 Update, Vibranium R1)
Windows 10 20H2 (October 2020 Update, Vibranium R2)
Windows 10 21H1 (May 2021 Update, Vibranium R3)
//0x4 bytes (sizeof)
enum _KI_CALLBACK
{
    KiCallbackNmi = 0,
    KiCallbackBound = 1,
    KiCallbackSx = 2,
    KiCallbackCount = 3,
    KiFirstCallback = 0
};