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//0x28 bytes (sizeof)
struct _SUBSECTION
{
    struct _CONTROL_AREA* ControlArea;                                      //0x0
    struct _MMPTE* SubsectionBase;                                          //0x4
    struct _SUBSECTION* NextSubsection;                                     //0x8
    union
    {
        struct _RTL_AVL_TREE GlobalPerSessionHead;                          //0xc
        struct _MI_CONTROL_AREA_WAIT_BLOCK* CreationWaitList;               //0xc
        struct _MI_PER_SESSION_PROTOS* SessionDriverProtos;                 //0xc
    };
    union
    {
        ULONG LongFlags;                                                    //0x10
        struct _MMSUBSECTION_FLAGS SubsectionFlags;                         //0x10
    } u;                                                                    //0x10
    ULONG StartingSector;                                                   //0x14
    ULONG NumberOfFullSectors;                                              //0x18
    ULONG PtesInSubsection;                                                 //0x1c
    union
    {
        struct _MI_SUBSECTION_ENTRY1 e1;                                    //0x20
        ULONG EntireField;                                                  //0x20
    } u1;                                                                   //0x20
    ULONG UnusedPtes:30;                                                    //0x24
    ULONG ExtentQueryNeeded:1;                                              //0x24
    ULONG DirtyPages:1;                                                     //0x24
};