You are building a service that needs to send HTTP requests to a large number of URLs (for example, a simple web crawler or data fetcher). The naive implementation processes URLs sequentially in a single thread, so total runtime is long. The interviewer asks two follow-up questions: 1. **If you want to speed up the overall processing, how would you change the design?** 2. **If you want to avoid sending too many requests at the same time (e.g., to respect rate limits or avoid overloading remote servers), how would you handle that?** Describe a high-level design that: - Increases throughput and reduces total completion time. - Controls how many requests are in flight simultaneously (globally and/or per host). You do not need to provide code, but clearly explain the main components (threading model, queues, rate limiting, etc.) and the trade-offs of your approach.