Uri C# extensions

gistfile1.txt

public static class Extensions
    {
        public static Uri Append(this Uri uri, params string[] paths)
        {
            return new Uri(paths.Aggregate(uri.AbsoluteUri, (current, path) =>
                    $"{current.TrimEnd('/')}/{path.TrimStart('/')}"));
        }

        public static Uri AppendQuery(this Uri uri, params string[] query)
        {
            var uriBuilder = new UriBuilder(uri) { Query = string.Join("&", query) };
            return uriBuilder.Uri;
        }

        public static Uri AppendQuery(this Uri uri, string query)
        {
            var uriBuilder = new UriBuilder(uri) { Query = query };
            return uriBuilder.Uri;
        }

        public static long ConvertToUnixTimestamp(this DateTime dateTime)
        {
            var utcDateTime = TimeZoneInfo.ConvertTimeToUtc(dateTime);
            var timeSpan = utcDateTime.Subtract(new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc));

            var unixTimestamp = (long)Math.Round(timeSpan.TotalSeconds, 0);
            return unixTimestamp;

        }
    }