System.Net.HttpListenerResponse.AddHeader C# (CSharp) Method

        public void AddHeader(string name, string value)
        {
            if (NetEventSource.IsEnabled) NetEventSource.Info(this, $"name={name}, value={value}");
            Headers.Set(name, value);
        }

		private static async Task ServeDirectoryListingAsync(DirectoryInfo root, DirectoryInfo directory, HttpListenerResponse response)
		{
			StringBuilder listBuilder = new StringBuilder();

			foreach (FileInfo file in directory.EnumerateFiles())
			{
				String target = directory.IsSameDirectory(root) ? file.Name
				                                                : Path.Combine(directory.Name, file.Name);
				listBuilder.AppendFormat("<li><a href=\"{0}\">{1}</a></li>", target, file.Name);
			}

			foreach (DirectoryInfo subDirectory in directory.EnumerateDirectories())
			{
				String target = directory.IsSameDirectory(root) ? subDirectory.Name
				                                                : Path.Combine(directory.Name, subDirectory.Name);
				listBuilder.AppendFormat("<li><a href=\"{0}\">{1}</a></li>", target, subDirectory.Name);
			}

			String htmlResponse = String.Format("<ul>{0}</ul>", listBuilder.ToString());

			response.ContentType = "text/html";
			response.ContentLength64 = htmlResponse.Length;
			response.AddHeader("Date", DateTime.Now.ToString("r"));

			response.StatusCode = (Int32)HttpStatusCode.OK; // Must be set before writing to OutputStream.

			using (StreamWriter writer = new StreamWriter(response.OutputStream))
			{
				await writer.WriteAsync(htmlResponse).ConfigureAwait(false);
			}
		}