Refactor refresh/revalidate behavior

* Rename two (unreleased) options to be more consistent with browser behavior:
    * `revalidate()` -> `refresh()`
    * `refresh()` -> `force_refresh()`
* Revert `RequestSettings` changes and use just kwargs instead for per-request settings
* Add full type hints back to extra kwargs for `CachedSession.send()`
* Fix a bug in which some kwargs specific to requests-cache could get passed to `requests.Session.send()`
* Use 'must-revalidate' as a temporary header for a user-requested refresh
* Refer to expiration value of 0 more accurately as 'expire immediately' rather than 'do not cache'
    * It may potentially be saved and used with revalidation, depending on other headers/settings
* `DO_NOT_CACHE` now has a different value but same effect
* Refer to constants in docs instead of 0, -1, etc.
* Log more details about post-read and pre-cache checks

1 files changed, 4 insertions, 2 deletions

diff --git a/requests_cache/backends/base.py b/requests_cache/backends/base.py
index f85c175..472ba9f 100644
--- a/requests_cache/backends/base.py
+++ b/requests_cache/backends/base.py
@@ -4,12 +4,14 @@
    :classes-only:
    :nosignatures:
 """
-import pickle
+from __future__ import annotations
+
 from abc import ABC
 from collections import UserDict
 from collections.abc import MutableMapping
 from datetime import datetime
 from logging import getLogger
+from pickle import PickleError
 from typing import Iterable, Iterator, Optional, Tuple, Union
 
 from requests import PreparedRequest, Response
@@ -21,7 +23,7 @@ from ..serializers import init_serializer
 from ..settings import DEFAULT_CACHE_NAME, CacheSettings
 
 # Specific exceptions that may be raised during deserialization
-DESERIALIZE_ERRORS = (AttributeError, ImportError, TypeError, ValueError, pickle.PickleError)
+DESERIALIZE_ERRORS = (AttributeError, ImportError, PickleError, TypeError, ValueError)
 
 ResponseOrKey = Union[CachedResponse, str]
 logger = getLogger(__name__)