requests使用断点续传时注意要加stream=True,不然你的硬盘可能会爆掉

res = requests.get(url, stream=True, headers=headers, verify=False)

        with open(dst, "ab") as f:

            dp = Down_progress(file_size, first_size, dst)

            dp.start()

            chunk_size = 1024

            for chunk in res.iter_content(chunk_size = chunk_size):

                if chunk:

                    f.write(chunk)

                    dp.update(chunk_size)