[错误] tiktoken 0.9.0 忽略了 TIKTOKEN_OFFLINE 和 TIKTOKEN_CACHE_DIR,仍然尝试网络下载

Bug Description

In offline environments (without internet connection), even if the TIKTOKEN_CACHE_DIR environment variable has been set correctly and the local cache file is complete, tiktoken==0.9.0 still attempts to download the encoding file from the network, resulting in a requests.exceptions.ConnectionError exception.