```typescript
/** An append-only log of timestamped events. */
export class EventLog {
  #events = [];

  /** Append one event. */
  record(event: { name: string; timestamp: number }): void;
  record(event: Event): void {
    throw new Error("Invalid argument type");
  }

  since(timestamp: number): Event[] {
    return this.#events.filter((event) => event.timestamp >= timestamp);
  }
}
```