Refactor task payload extraction and update workflow builder

Modified the way task payload is extracted in the OrderFoodTaskHandler.cs for more robustness. The input parameter of the workflow builder in the HungryWorkflow.cs file has also been refactored for efficiency. Making these tweaks streamlines management of values within the tasks.

src/samples/aspnet/Elsa.Samples.AspNet.RunTaskIntegration/Handlers/OrderFoodTaskHandler.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Threading;
 using System.Threading.Tasks;
+using Elsa.Extensions;
 using Elsa.Mediator.Contracts;
 using Elsa.Workflows.Runtime.Contracts;
 using Elsa.Workflows.Runtime.Notifications;
@@ -21,8 +22,8 @@ public async Task HandleAsync(RunTaskRequest notification, CancellationToken can
  if (notification.TaskName != "OrderFood")
  return;
 
- var args = (dynamic)notification.TaskPayload!;
- var foodName = args.Food;
+ var args = notification.TaskPayload!;
+ var foodName = args.GetValue<string>("Food");
 
  Console.WriteLine("Preparing {0}...", foodName);
  await Task.Delay(1000, cancellationToken);

src/samples/aspnet/Elsa.Samples.AspNet.RunTaskIntegration/Workflows/HungryWorkflow.cs

@@ -14,7 +14,7 @@ public class HungryWorkflow : WorkflowBase
 {
  protected override void Build(IWorkflowBuilder builder)
  {
- var deliveredFood = new Variable<string>();
+ var deliveredFood = builder.WithVariable<string>();
 
  builder.Root = new Sequence
  {
@@ -29,7 +29,7 @@ protected override void Build(IWorkflowBuilder builder)
  new WriteLine("Hunger detected!"),
  new RunTask("OrderFood")
  {
- Payload = new(new Dictionary<string, object>() { ["Food"] = "Pizza" }),
+ Payload = new(new Dictionary<string, object> { ["Food"] = "Pizza" }),
  Result = new Output<object>(deliveredFood)
  },
  new WriteLine(context => $"Eating the {deliveredFood.Get(context)}"),