_KI_CALLBACK

Windows 10 1607 | Server 2016 (Anniversary Update, Redstone 1)
Windows 10 1703 (Creators Update, Redstone 2)
Windows 10 1709 (Fall Creators Update, Redstone 3)
//0x4 bytes (sizeof)
enum _KI_CALLBACK
{
    KiCallbackNmi = 0,
    KiCallbackBound = 1,
    KiCallbackCount = 2,
    KiFirstCallback = 0
};