Trigger view rendering asynchronously.

This is as simple as modifying the base class to return task and await the ExecuteAsync method.  Also added a piece to the sample project to verify functionality.

samples/MvcSample.Web/Views/Shared/MyView.cshtml

@@ -6,6 +6,13 @@
     string nullValue = null;
 }
 
+@functions {
+    public async Task<string> AsyncValueRetrieval()
+    {
+        return "Hello World";
+    }
+}
+
 <div class="jumbotron">
     <h1>ASP.NET</h1>
     <p class="lead">ASP.NET is a free web framework for building great Web sites and Web applications using HTML, CSS and JavaScript.</p>
@@ -13,7 +20,8 @@
 </div>
 <div class="row">
     <h3 title="@Model.Name" class="@nullValue">Hello @Model.Name! Happy @Model.Age birthday.</h3>
-    
+    <h3>This value was retrieved asynchronously: @(await AsyncValueRetrieval())</h3>
+
     <div class="col-md-4">
         <h2>Getting started</h2>
         <p>

src/Microsoft.AspNet.Mvc.Razor.Host/MvcRazorHost.cs

@@ -32,7 +32,7 @@ namespace Microsoft.AspNet.Mvc.Razor
             _baseType = baseType;
             DefaultBaseClass = baseType + "<dynamic>";
             GeneratedClassContext = new GeneratedClassContext(
-                executeMethodName: "Execute",
+                executeMethodName: "ExecuteAsync",
                 writeMethodName: "Write",
                 writeLiteralMethodName: "WriteLiteral",
                 writeToMethodName: "WriteTo",

src/Microsoft.AspNet.Mvc.Razor/RazorView.cs

@@ -31,7 +31,7 @@ namespace Microsoft.AspNet.Mvc.Razor
             using (var bodyWriter = new StringWriter(contentBuilder))
             {
                 Output = bodyWriter;
-                Execute();
+                await ExecuteAsync();
             }
 
             var bodyContent = contentBuilder.ToString();
@@ -60,7 +60,7 @@ namespace Microsoft.AspNet.Mvc.Razor
             await layoutView.RenderAsync(context, writer);
         }
 
-        public abstract void Execute();
+        public abstract Task ExecuteAsync();
 
         public virtual void Write(object value)
         {