Improved cookie provider

Author: FlorianRappl

src/AngleSharp.Io/Cookie/AdvancedCookieProvider.cs

@@ -169,6 +169,7 @@ public void AddCookie(WebCookie cookie)
             {
                 _cookies.Remove(FindCookie(cookie.Domain, cookie.Path, cookie.Key));
                 InsertCookie(cookie);
+                WriteCookies();
             }
         }
 
@@ -251,7 +252,6 @@ private void InsertCookie(WebCookie cookie)
             }
 
             _cookies.Add(cookie);
-            WriteCookies();
         }
 
         private void WriteCookies()

src/AngleSharp.Io/Cookie/LocalFileHandler.cs

@@ -17,7 +17,8 @@ public class LocalFileHandler : ICookieFileHandler
         /// <param name="filePath">The path to resolve to.</param>
         public LocalFileHandler(String filePath) => _filePath = filePath;
 
-        String ICookieFileHandler.ReadFile() => File.ReadAllText(_filePath);
+        String ICookieFileHandler.ReadFile() => File.Exists(_filePath) ?
+            File.ReadAllText(_filePath) : String.Empty;
 
         void ICookieFileHandler.WriteFile(String content)
         {

src/AngleSharp.Io/IoConfigurationExtensions.cs

@@ -72,14 +72,29 @@ public static IConfiguration WithStandardDownload(this IConfiguration configurat
         /// <param name="configuration">The configuration to use.</param>
         /// <returns>The new configuration.</returns>
         public static IConfiguration WithRequesters(this IConfiguration configuration) =>
-            configuration.WithRequesters(new HttpClientHandler { UseCookies = false, AllowAutoRedirect = false });
+            configuration.WithRequesters(new HttpClientHandler());
+
+        /// <summary>
+        /// Adds the requesters from the AngleSharp.Io package.
+        /// </summary>
+        /// <param name="configuration">The configuration to use.</param>
+        /// <param name="httpClientHandler">
+        /// The HTTP client handler to use for sending requests.
+        /// </param>
+        /// <returns>The new configuration.</returns>
+        public static IConfiguration WithRequesters(this IConfiguration configuration, HttpClientHandler httpClientHandler)
+        {
+            httpClientHandler.UseCookies = false;
+            httpClientHandler.AllowAutoRedirect = false;
+            return configuration.WithRequesters((HttpMessageHandler)httpClientHandler);
+        }
 
         /// <summary>
         /// Adds the requesters from the AngleSharp.Io package.
         /// </summary>
         /// <param name="configuration">The configuration to use.</param>
         /// <param name="httpMessageHandler">
-        /// The HTTP handler stack to use for sending requests.
+        /// The HTTP message handler to use for sending requests.
         /// </param>
         /// <returns>The new configuration.</returns>
         public static IConfiguration WithRequesters(this IConfiguration configuration, HttpMessageHandler httpMessageHandler)