public static ReadOnlySpan <char> TrimEnd(this ReadOnlySpan <char> span, ReadOnlySpan <char> trimChars) { if (trimChars.IsEmpty) { return(span.TrimEnd()); } int end = span.Length - 1; for (; end >= 0; end--) { for (int i = 0; i < trimChars.Length; i++) { if (span[end] == trimChars[i]) { goto Next; } } break; Next: ; } return(span.Slice(0, end + 1)); }