dead lock

tiktoken.registry.get_encoding，there is a lock
but first time i invoke it, it will request "https://openaipublic.blob.core.windows.net/encodings/cl100k_base.tiktoken",and final will invoke tiktoken.load.read_file_cached, if contents = read_file(blobpath) network error, there is not set request timeout, when next query come in ,will deadlock

`def get_encoding(encoding_name: str) -> Encoding:
if not isinstance(encoding_name, str):
raise ValueError(f"Expected a string in get_encoding, got {type(encoding_name)}")

if encoding_name in ENCODINGS:
    return ENCODINGS[encoding_name]

with _lock:
    if encoding_name in ENCODINGS:
        return ENCODINGS[encoding_name]

    if ENCODING_CONSTRUCTORS is None:
        _find_constructors()
        assert ENCODING_CONSTRUCTORS is not None

    if encoding_name not in ENCODING_CONSTRUCTORS:
        raise ValueError(
            f"Unknown encoding {encoding_name}.\n"
            f"Plugins found: {_available_plugin_modules()}\n"
            f"tiktoken version: {tiktoken.__version__} (are you on latest?)"
        )

    constructor = ENCODING_CONSTRUCTORS[encoding_name]
    enc = Encoding(**constructor())
    ENCODINGS[encoding_name] = enc
    return enc`

`def read_file_cached(blobpath: str, expected_hash: str | None = None) -> bytes:
user_specified_cache = True
if "TIKTOKEN_CACHE_DIR" in os.environ:
cache_dir = os.environ["TIKTOKEN_CACHE_DIR"]
elif "DATA_GYM_CACHE_DIR" in os.environ:
cache_dir = os.environ["DATA_GYM_CACHE_DIR"]
else:
import tempfile

    cache_dir = os.path.join(tempfile.gettempdir(), "data-gym-cache")
    user_specified_cache = False

if cache_dir == "":
    # disable caching
    return read_file(blobpath)

cache_key = hashlib.sha1(blobpath.encode()).hexdigest()

cache_path = os.path.join(cache_dir, cache_key)
if os.path.exists(cache_path):
    with open(cache_path, "rb") as f:
        data = f.read()
    if expected_hash is None or check_hash(data, expected_hash):
        return data

    # the cached file does not match the hash, remove it and re-fetch
    try:
        os.remove(cache_path)
    except OSError:
        pass

contents = read_file(blobpath)
if expected_hash and not check_hash(contents, expected_hash):
    raise ValueError(
        f"Hash mismatch for data downloaded from {blobpath} (expected {expected_hash}). "
        f"This may indicate a corrupted download. Please try again."
    )

import uuid

try:
    os.makedirs(cache_dir, exist_ok=True)
    tmp_filename = cache_path + "." + str(uuid.uuid4()) + ".tmp"
    with open(tmp_filename, "wb") as f:
        f.write(contents)
    os.rename(tmp_filename, cache_path)
except OSError:
    # don't raise if we can't write to the default cache, e.g. issue #75
    if user_specified_cache:
        raise

return contents`

Start by tracing tiktoken.registry.get_encoding into tiktoken.load.read_file_cached and inspect the network path used by read_file. Reproduce a failed download, then verify that a later get_encoding call can proceed after the failure. Done means the reported failure no longer leaves subsequent encoding lookups blocked.