Extend the .NET HTTPContent class (used by HTTPClient) to download files, with usage example

HttpContentExtensions.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace Basic
{
    public static class HttpContentExtensions
    {
        public static Task ReadAsFileAsync(this HttpContent content, string filename, bool overwrite)
        {
            string pathname = Path.GetFullPath(filename);
            if (!overwrite && File.Exists(filename))
            {
                throw new InvalidOperationException(string.Format("File {0} already exists.", pathname));
            }

            FileStream fileStream = null;
            try
            {
                fileStream = new FileStream(pathname, FileMode.Create, FileAccess.Write, FileShare.None);
                return content.CopyToAsync(fileStream).ContinueWith(
                    (copyTask) =>
                    {
                        fileStream.Close();
                    });
            }
            catch
            {
                if (fileStream != null)
                {
                    fileStream.Close();
                }

                throw;
            }
        }
    }
    
    public class Program
    {
 	    static void Main(string[] args)
       {
          RunAsync().Wait();
          Console.ReadKey();
        }
        static async Task RunAsync()
        {
          var creds = new NetworkCredential("root", "P@ssw0rd");
          var handler = new HttpClientHandler {Credentials = creds};
            
          HttpClient client = new HttpClient(handler);
          var bytearray = Encoding.ASCII.GetBytes("root:P@ssw0rd");

          // Ye olde way of doing authentication pre-dotnet 4.5
          //client2.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(bytearray));

          await client.GetAsync(@"https://esxi/host/license.cfg").ContinueWith(
              (requestTask) =>
              {
                  HttpResponseMessage fileHttpResponseMessage = requestTask.Result;

                  fileHttpResponseMessage.EnsureSuccessStatusCode();

                  fileHttpResponseMessage.Content.ReadAsFileAsync(@"D:\Lic.cfg", true).ContinueWith(
                      (help) =>
                      {
                          Console.Write("A");
                      });
              });

            await client.GetAsync(@"https://esxi/host/hostd.log").ContinueWith(
               (requestTask) =>
               {
                   HttpResponseMessage fileHttpResponseMessage = requestTask.Result;

                   fileHttpResponseMessage.EnsureSuccessStatusCode();

                   fileHttpResponseMessage.Content.ReadAsFileAsync(@"D:\hostd.log", true).ContinueWith(
                       (help) =>
                       {
                           Console.Write("B");
                       });
               });

        }
   }
}