SIPSorcery.SIP.SIPHeader.GetUnknownHeaderValue C# (CSharp) Method

        public string GetUnknownHeaderValue(string unknownHeaderName)
        {
            if (unknownHeaderName.IsNullOrBlank())
            {
                return null;
            }
            else if (UnknownHeaders == null || UnknownHeaders.Count == 0)
            {
                return null;
            }
            else
            {
                foreach (string unknonwHeader in UnknownHeaders)
                {
                    string trimmedHeader = unknonwHeader.Trim();
                    int delimiterIndex = trimmedHeader.IndexOf(SIPConstants.HEADER_DELIMITER_CHAR);

                    if (delimiterIndex == -1)
                    {
                        logger.Warn("Invalid SIP header, ignoring, " + unknonwHeader + ".");
                        continue;
                    }

                    string headerName = trimmedHeader.Substring(0, delimiterIndex).Trim();

                    if (headerName.ToLower() == unknownHeaderName.ToLower())
                    {
                        return trimmedHeader.Substring(delimiterIndex + 1).Trim();
                    }
                }

                return null;
            }
        }