Connect on first use

Connect to the database on first use, then reuse the connection. Two requests at startup both see no connection yet, and both connect.

src/lazy-connect.ts

export function lazyConnect<T>(connect: () => Promise<T>) {
  let db: T | undefined;
  return async () => {
    if (!db) db = await connect();
    return db;
  };
}

See how TLA+ finds and fixes it.