Add missing async methods to GXDataArea

Author: claudiamurialdo

dotnet/src/dotnetframework/GxClasses/Middleware/GXHttp.cs

@@ -3235,6 +3235,20 @@ public virtual void master_styles() { }
 	}
 	public abstract class GXDataArea : GXHttpHandler
 	{
+#if NETCORE
+		public virtual Task ExecuteStartEventAsync()
+		{
+			return Task.CompletedTask;
+		}
+		public virtual Task RenderHtmlContentAsync()
+		{
+			return Task.CompletedTask;
+		}
+		public virtual Task DispatchEventsAsync()
+		{
+			return Task.CompletedTask;
+		}
+#endif
 		abstract public short ExecuteStartEvent();
 		abstract public void RenderHtmlHeaders();
 		abstract public void RenderHtmlOpenForm();