下载 CDN 图片/视频很慢或超时怎么办？

{/* /etc/resolv.conf */}
nameserver 1.1.1.1        # Cloudflare
nameserver 8.8.8.8        # Google
nameserver 223.5.5.5      # 阿里 DNS
nameserver 119.29.29.29   # 腾讯 DNS

import time
import httpx

# 连接 10 秒；读取 30 秒 = 多久没收到数据就放弃（不是总时长）
TIMEOUT = httpx.Timeout(connect=10, read=30, write=30, pool=10)

def download(url: str, path: str, attempts: int = 4) -> str:
    for i in range(attempts):
        try:
            with httpx.stream("GET", url, timeout=TIMEOUT, follow_redirects=True) as resp:
                resp.raise_for_status()
                with open(path, "wb") as f:
                    for chunk in resp.iter_bytes(chunk_size=256 * 1024):
                        f.write(chunk)
            return path
        except httpx.HTTPError as e:
            print(f"下载失败（第 {i + 1} 次）：{e!r}")
            time.sleep(2 * (i + 1))
    raise RuntimeError(f"图片已生成，但下载多次失败：{url}")

download("<CDN URL>", "output.png")

aria2c -x 8 -s 8 -k 1M --file-allocation=none "<CDN URL>"