On Windows, a mouse can report higher resolution scroll events by returning a value that is not a multiple of WHEEL_DELTA.

As in, delta can be a value like 1.

Ok(WM_MOUSEHWHEEL) => {
            let delta = get_delta(lpdata) as c_short;
            Some(EventType::Wheel {
                delta_x: (delta / WHEEL_DELTA) as i64,
                delta_y: 0,
            })
        }

This library should ideally expose that information.

There's also another variant of high resolution scrolling (pixel level scrolling, used for touchscreens), but that's a separate issue. See also https://docs.rs/winit/latest/winit/event/enum.MouseScrollDelta.html