System.Net.Mail.Message.IsHeaderSet C# (CSharp) Method

        private bool IsHeaderSet(string headerName)
        {
            for (int i = 0; i < Headers.Count; i++)
            {
                if (string.Equals(Headers.GetKey(i), headerName, StringComparison.InvariantCultureIgnoreCase))
                {
                    return true;
                }
            }
            return false;
        }