Function discuss 

pub async fn discuss(
    runtime: &dyn AgentRuntime,
    agents: &[Agent],
    topic: &str,
    rounds: usize,
    cancel: CancellationToken,
    events: Sender<AgentEvent>,
) -> Result<String>

The ONLY orchestration primitive in the kernel.

Runs a fixed-N-round multi-agent discussion, emitting AgentEvents via the provided channel. No convergence logic — runs exactly rounds rounds. Caller controls policy through rounds and cancel.

The primary agent (agents[0]) provides the final summary.