Implemented ExecuteAsync overload as an extension method of IRestClient.

The concrete implementation `RestClient` has a nice `ExecuteAsync` method that's simply a wrapper to a call of another method on `IRestClient`. Since this method can be completely implemented in terms of the `IRestClient` interface, it makes sense to make it an extension method of `IRestClient`. The benefit is that I don't need to pass around a `RestClient` in my own API but I can pass around an `IRestClient`. Makes unit testing easier too, and that comes for free! Added bonus! :)

Author: haacked

RestSharp/RestClient.Async.cs

@@ -25,17 +25,6 @@ namespace RestSharp
 {
 	public partial class RestClient
 	{
-
-		/// <summary>
-		/// Executes the request and callback asynchronously, authenticating if needed
-		/// </summary>
-		/// <param name="request">Request to be executed</param>
-		/// <param name="callback">Callback function to be executed upon completion</param>
-		public virtual RestRequestAsyncHandle ExecuteAsync(IRestRequest request, Action<RestResponse> callback)
-		{
-			return ExecuteAsync(request, (response, handle) => callback(response));
-		}
-
 		/// <summary>
 		/// Executes the request and callback asynchronously, authenticating if needed
 		/// </summary>

RestSharp/RestClientExtensions.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace RestSharp
+{
+    public static class RestClientExtensions
+    {
+        /// <summary>
+        /// Executes the request and callback asynchronously, authenticating if needed
+        /// </summary>
+        /// <param name="client">The IRestClient this method extends</param>
+        /// <param name="request">Request to be executed</param>
+        /// <param name="callback">Callback function to be executed upon completion</param>
+        public static RestRequestAsyncHandle ExecuteAsync(this IRestClient client, IRestRequest request, Action<RestResponse> callback)
+        {
+            return client.ExecuteAsync(request, (response, handle) => callback(response));
+        }
+    }
+}

RestSharp/RestSharp.csproj

@@ -107,6 +107,7 @@
     <Compile Include="Extensions\MonoHttp\Helpers.cs" />
     <Compile Include="Extensions\MonoHttp\HtmlEncoder.cs" />
     <Compile Include="Extensions\MonoHttp\HttpUtility.cs" />
+    <Compile Include="RestClientExtensions.cs" />
     <Compile Include="Extensions\StringExtensions.cs" />
     <Compile Include="Http.Sync.cs" />
     <Compile Include="HttpCookie.cs" />