unsafe fn convert_int_from_jsval<T, M>(
    cx: *mut JSContext,
    value: HandleValue<'_>,
    option: ConversionBehavior,
    convert_fn: unsafe fn(_: *mut JSContext, _: HandleValue<'_>) -> Result<M, ()>
) -> Result<ConversionResult<T>, ()>where
    T: Bounded + Zero + As<f64>,
    M: Zero + As<T>,
    f64: As<T>,