OptionalreplyFor: (text: string) => stringTears down the conversation/session resources.
Arms a one-shot failure on the next SendMessage (test helper for graceful-degradation paths).
Initializes the transport with the freshly-minted guest session.
Sends a user message and resolves with the agent's reply. The pinned agent id from the session is ALWAYS passed as explicitAgentId (D5) — the transport never lets the caller pick an arbitrary agent.
OptionalonProgress: WidgetProgressCallbackUpdates the held token after a refresh (no reconnection of the conversation).
Deterministic, dependency-free transport for tests + the demo host page.