System.Net.Http.Headers.NameValueHeaderValue.CheckValueFormat C# (CSharp) Method

        private static void CheckValueFormat(string value)
        {
            // Either value is null/empty or a valid token/quoted string
            if (!(string.IsNullOrEmpty(value) || (GetValueLength(value, 0) == value.Length)))
            {
                throw new FormatException(string.Format(System.Globalization.CultureInfo.InvariantCulture, SR.net_http_headers_invalid_value, value));
            }
        }

 private static void CheckNameValueFormat(string name, string value)
 {
     HeaderUtilities.CheckValidToken(name, nameof(name));
     NameValueHeaderValue.CheckValueFormat(value);
 }