[Bug]: TaskUpdater's start_work publishes TaskStatusUpdateEvent instead of Task

What happened?

start_work in TaskUpdater uses the update_status method, which publishes a TaskStatusUpdateEvent. However, from the 9.3. Streaming Task Execution (SSE) example in the specifications, when a task is started, it should be a Task event, with status being submitted (or working should be ok too?).

a2a-python/src/a2a/server/tasks/task_updater.py

Lines 153 to 158 in 1dbe33d

    
           async def start_work(self, message: Message | None = None) -> None: 
        
               """Marks the task as working and publishes a status update.""" 
        
               await self.update_status( 
        
                   TaskState.working, 
        
                   message=message, 
        
               )

Relevant log output

N/A

Code of Conduct

I agree to follow this project's Code of Conduct

hi, you can create a new task object, enqueue the task and use the TaskUpdater to mutate the task.

Here is an example - https://github.com/a2aproject/a2a-samples/blob/883c8906a60cb48e43599db0480d2217bd02c320/samples/python/agents/langgraph/app/agent_executor.py#L45

	async def start_work(self, message: Message \| None = None) -> None:
	"""Marks the task as working and publishes a status update."""
	await self.update_status(
	TaskState.working,
	message=message,
	)