Provide typed tasks.

pkg/tasks/example.go

@@ -1,9 +1,9 @@
 package tasks
 
-// TypeExample is the type for the example task.
-// This is what is passed in to TaskClient.New() when creating a new task
-const TypeExample = "example_task"
-
 type ExampleTask struct {
 	Message string
 }
+
+func (t ExampleTask) Name() string {
+	return "example_task"
+}