public static int IndexWhere <T>(this ISeq <T> seq, Func <T, bool> predicate) { return(seq.IndexWhere(predicate, 0, seq.Length)); }
public static int IndexOf <T>(this ISeq <T> seq, object element, int start, int end) { return(element != null ? seq.IndexWhere(e => element.Equals(e), start, end) : seq.IndexWhere(e => e == null, start, end)); }