Dynamic membership in an AgentChat team

[ekzhu]

What feature would you like to be added?

Before the task during initialization:

# Initialization
team = Team(...)
team.add(Agent(...))
team.add(Agent(...))

# Run the task.
result = await team.run(...)

Alternatively, during an execution of a task.

team = Team(...)
# Running the task in the background
task = asyncio.create_task(team.run(...))

# Add an agent.
await team.add(Agent(...))

# Remove an agent.
await team.remove(name=...)

# Waiting for the task to finish.
await task

Why is this needed?

It's cool!

Please comment here for usage cases.