typedef struct _MMSUBSECTION_NODE
{
    union
    {
        unsigned long LongFlags;
        MMSUBSECTION_FLAGS SubsectionFlags;
    } u;
    unsigned long StartingSector;
    unsigned long NumberOfFullSectors;
    union
    {
        __int64 Balance : 2;
        MMSUBSECTION_NODE *Parent;
    } u1;
    MMSUBSECTION_NODE *LeftChild;
    MMSUBSECTION_NODE *RightChild;
} MMSUBSECTION_NODE, *PMMSUBSECTION_NODE;