Как мне маршалировать структуру C# с полями делегата?

Я пишу оболочку C# для SDL3. В настоящее время я пытаюсь реализовать следующую структуру:

typedef struct SDL_VirtualJoystickDesc
{
    Uint16 type;        /**< `SDL_JoystickType` */
    Uint16 padding;     /**< unused */
    Uint16 vendor_id;   /**< the USB vendor ID of this joystick */
    Uint16 product_id;  /**< the USB product ID of this joystick */
    Uint16 naxes;       /**< the number of axes on this joystick */
    Uint16 nbuttons;    /**< the number of buttons on this joystick */
    Uint16 nballs;      /**< the number of balls on this joystick */
    Uint16 nhats;       /**< the number of hats on this joystick */
    Uint16 ntouchpads;  /**< the number of touchpads on this joystick, requires `touchpads` to point at valid descriptions */
    Uint16 nsensors;    /**< the number of sensors on this joystick, requires `sensors` to point at valid descriptions */
    Uint16 padding2[2]; /**< unused */
    Uint32 button_mask; /**< A mask of which buttons are valid for this controller
                             e.g. (1 << SDL_GAMEPAD_BUTTON_SOUTH) */
    Uint32 axis_mask;   /**< A mask of which axes are valid for this controller
                             e.g. (1 << SDL_GAMEPAD_AXIS_LEFTX) */
    const char *name;   /**< the name of the joystick */
    const SDL_VirtualJoystickTouchpadDesc *touchpads;   /**< A pointer to an array of touchpad descriptions, required if `ntouchpads` is > 0 */
    const SDL_VirtualJoystickSensorDesc *sensors;       /**< A pointer to an array of sensor descriptions, required if `nsensors` is > 0 */

    void *userdata;     /**< User data pointer passed to callbacks */
    void (SDLCALL *Update)(void *userdata); /**< Called when the joystick state should be updated */
    void (SDLCALL *SetPlayerIndex)(void *userdata, int player_index); /**< Called when the player index is set */
    int (SDLCALL *Rumble)(void *userdata, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble); /**< Implements SDL_RumbleJoystick() */
    int (SDLCALL *RumbleTriggers)(void *userdata, Uint16 left_rumble, Uint16 right_rumble); /**< Implements SDL_RumbleJoystickTriggers() */
    int (SDLCALL *SetLED)(void *userdata, Uint8 red, Uint8 green, Uint8 blue); /**< Implements SDL_SetJoystickLED() */
    int (SDLCALL *SendEffect)(void *userdata, const void *data, int size); /**< Implements SDL_SendJoystickEffect() */
    int (SDLCALL *SetSensorsEnabled)(void *userdata, SDL_bool enabled); /**< Implements SDL_SetGamepadSensorEnabled() */
} SDL_VirtualJoystickDesc;

Эта структура используется в следующей функции C:

extern SDL_DECLSPEC SDL_JoystickID SDLCALL SDL_AttachVirtualJoystick(const SDL_VirtualJoystickDesc *desc);

Моя (наивная) реализация C# для SDL_VirtualJoystickDesc:

[StructLayout(LayoutKind.Sequential)]
public unsafe struct SDL_VirtualJoystickDesc
{
    /// <summary>
    /// A value from <see cref = "SDL_JoystickType"/>.
    /// </summary>
    public SDL_JoystickType Type;

    private readonly ushort _padding1;

    /// <summary>
    /// The USB vendor ID of this joystick.
    /// </summary>
    public ushort VendorId;

    /// <summary>
    /// The USB product ID of this joystick.
    /// </summary>
    public ushort ProductId;

    /// <summary>
    /// The number of axes on this joystick.
    /// </summary>
    public ushort NAxes;

    /// <summary>
    /// The number of buttons on this joystick.
    /// </summary>
    public ushort NButtons;

    /// <summary>
    /// The number of balls on this joystick.
    /// </summary>
    public ushort NBalls;

    /// <summary>
    /// The number of hats on this joystick.
    /// </summary>
    public ushort NHats;

    /// <summary>
    /// The number of touchpads on this joystick, requires <see cref = "Touchpads"/> to point at valid descriptions
    /// </summary>
    public ushort NTouchpads;

    /// <summary>
    /// The number of sensors on this joystick, requires <see cref = "Sensors"/> to point at valid descriptions.
    /// </summary>
    public ushort NSensors;

    private readonly ushort _padding2;

    private readonly ushort _padding3;

    /// <summary>
    /// A mask of which buttons are valid for this controller, e.g. (1 << <see cref = "SDL_GamepadButton.South"/>).
    /// </summary>
    public uint ButtonMask;

    /// <summary>
    /// A mask of which axes are valid for this controller, e.g. (1 << <see cref = "SDL_GamepadAxis.LeftX"/>).
    /// </summary>
    public uint AxisMask;

    /// <summary>
    /// The name of the joystick.
    /// </summary>
    public readonly string Name => Marshal.PtrToStringUTF8((nint)_name)!;

    private readonly byte* _name;

    /// <summary>
    /// A pointer to an array of touchpad descriptions, required if <see cref = "NTouchpads"/> is > 0.
    /// </summary>
    public SDL_VirtualJoystickTouchpadDesc* Touchpads;

    /// <summary>
    /// A pointer to an array of sensor descriptions, required if <see cref = "NSensors"/> is > 0.
    /// </summary>
    public SDL_VirtualJoystickSensorDesc* Sensors;

    /// <summary>
    /// User data pointer passed to callbacks.
    /// </summary>
    public void* UserData;

    /// <summary>
    /// Called when the joystick state should be updated.
    /// </summary>
    [MarshalAs(UnmanagedType.FunctionPtr)]
    public SDL_VirtualJoystickUpdateCallback Update;

    /// <summary>
    /// Called when the player index is set.
    /// </summary>
    [MarshalAs(UnmanagedType.FunctionPtr)]
    public SDL_VirtualJoysticSetPlayerIndexCallback SetPlayerIndex;

    /// <summary>
    /// Implements <see cref = "SDL.RumbleJoystick(SDL_Joystick*, ushort, ushort, uint)"/>.
    /// </summary>
    [MarshalAs(UnmanagedType.FunctionPtr)]
    public SDL_VirtualJoysticRumbleCallback Rumble;

    /// <summary>
    /// Implements <see cref = "SDL.RumbleJoystickTriggers(SDL_Joystick*, ushort, ushort, uint)"/>.
    /// </summary>
    [MarshalAs(UnmanagedType.FunctionPtr)]
    public SDL_VirtualJoysticRumbleTriggersCallback RumbleTriggers;

    /// <summary>
    /// Implements <see cref = "SDL.SetJoystickLED(SDL_Joystick*, byte, byte, byte)"/>.
    /// </summary>
    [MarshalAs(UnmanagedType.FunctionPtr)]
    public SDL_VirtualJoysticSetLEDCallback SetLED;

    /// <summary>
    /// Implements <see cref = "SDL.SendJoystickEffect(SDL_Joystick*, void*, int)"/>.
    /// </summary>
    [MarshalAs(UnmanagedType.FunctionPtr)]
    public SDL_VirtualJoysticSendEffectCallback SendEffect;

    /// <summary>
    /// Implements <see cref = "SDL.SetGamepadSensorEnabled(SDL_Gamepad*, SDL_SensorType, bool)"/>.
    /// </summary>
    [MarshalAs(UnmanagedType.FunctionPtr)]
    public SDL_VirtualJoysticSetSensorsEnabledCallback SetSensorsEnabled;
}

Я реализовал указатели функций с помощью делегатов, примерно так:

[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public unsafe delegate void SDL_VirtualJoystickUpdateCallback(void* userData);

Остальные делегаты реализовали то же самое.

Но при попытке реализовать функцию SDL_AttachVirtualJoystick компилятор CS8500 предупреждает меня: «Это принимает адрес, размер или объявляет указатель на управляемый тип [...]»

Реализация функции на языке C# выглядит следующим образом:

[DllImport(LibraryName, CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
public static extern SDL_JoystickId SDL_AttachVirtualJoystick(SDL_VirtualJoystickDesc* desc);

SDL_JoystickId — это просто перечисление.

Я понимаю, что делегаты являются управляемыми типами, поэтому я не могу легко получить адреса их памяти. Я также знаю, что могу реализовать эти поля как nint и использовать Marshal.GetFunctionPointerForDelegate(), но я не уверен, что это наиболее подходящий способ.

Мой вопрос: каков будет правильный способ реализации этой структуры?