public static Tasks.Task <int> Index <T>(this IAsyncEnumerator <T> me, params T[] needles)
where T : IEquatable <T>
{
return(me.Index(element => needles.Contains(element)));
}
public static Tasks.Task <int> Index <T>(this IAsyncEnumerator <T> me, T needle)
{
return(me.Index(element => element.SameOrEquals(needle)));
}