Function SetupUnityCallbacks 

#[unsafe(no_mangle)]
pub extern "C" fn SetupUnityCallbacks(
    get_axis_description: extern "C" fn(i32, *mut i8, *mut i8, *mut i8) -> i32,
    configure_axis: extern "C" fn(i32, i32),
    get_resolutions: extern "C" fn(u32) -> *mut CppVector<(u32, u32)>,
    get_selected_resolution: extern "C" fn(*mut u32, *mut u32, *mut bool),
    set_selected_resolution: extern "C" fn(u32, u32, bool),
    get_quality_levels: extern "C" fn() -> *mut CppVector<*const i8>,
    get_selected_quality_level: extern "C" fn() -> i32,
    set_selected_quality_level: extern "C" fn(i32),
    get_displays: extern "C" fn() -> *mut CppVector<*const i8>,
    get_selected_display: extern "C" fn() -> u32,
    set_selected_display: extern "C" fn(u32),
)

Sets the callbacks from Unity.