Chat screen on a secondary runtime

const CHAT_RUNTIME_NAMES = conversations.map(
  conversation => `conversation-${conversation.id}-runtime`,
);

function ConversationPicker() {
  const [selectedId, setSelectedId] = useState<string | null>(null);

  useEffect(() => {
    if (selectedId != null) {
      return;
    }

    for (const runtimeName of CHAT_RUNTIME_NAMES) {
      void ThreadedRuntime.prewarm(runtimeName);
    }
  }, [selectedId]);

  if (selectedId) {
    return (
      <ThreadedScreen
        component={ConversationScreen}
        props={{ conversationId: selectedId }}
        runtimeName={`conversation-${selectedId}-runtime`}
      />
    );
  }

  return (
    <ConversationList
      onOpen={conversationId => {
        void ThreadedRuntime.prewarm(`conversation-${conversationId}-runtime`);
        setSelectedId(conversationId);
      }}
    />
  );
}