Request: "What is the capital of France?"
→ Compute embedding
→ Check cache for similar queries
→ HIT! Return cached response in ~5ms

X-Raptor-Cache: hit              # or "miss"
X-Raptor-Latency-Ms: 5           # Total Raptor time
X-Raptor-Upstream-Latency-Ms: 0  # 0 on cache hit

# This hits cache and streams just like the original
stream = client.chat.completions.create(
    model="gpt-4",
    messages=[{"role": "user", "content": "What's the capital of France?"}],
    stream=True
)