How does one Add a delay to a prefix of an IEnumerator?

[CatsArmy]

im trying to add a delay to an IEnumerator (not a IEnumerator btw) and im unable to add a delay to it ive tried many diffrent ways to do it. ive thought about using an transplier but i could find how i would add a delay and do what i need to do with it.
no where in the docs does it give an example of how to do it as a prefix only a post fix if you cant do it as a prefix like that i would suggest adding that to the docs as i couldnt find anywhere that said that.

private static readonly WaitForSeconds Delay = new WaitForSeconds(delay);
[HarmonyPrefix]
[HarmonyPatch(nameof(PlayerControllerB.PlayerJump))]
private static IEnumerator MyWrapper(PlayerControllerB __instance, IEnumerator __result)
{
    //Run prefix?
    yield return Delay;
    InputAction Jump = GetJump();

    if (Jump.IsInProgress() && Jump.IsPressed())//performed == on button up
    {
        // Run original enumerator code
        while (__result.MoveNext())
        {
            yield return __result.Current;
        }
    }
    else
    {
        __instance.isCrouching = true;
    }
    // Run your postfix
}

[HarmonyPrefix]
[HarmonyPatch(nameof(PlayerControllerB.PlayerJump))]

public static IEnumerator _Prefix_PlayerJump(PlayerControllerB __instance, IEnumerator __results)
{
    yield return Delay;
    InputAction Jump = GetJump();
    if (!Jump.IsInProgress() || !Jump.IsPressed())//performed == on button up
    {
        __instance.isCrouching = true;
    }
    yield return __results;

}