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, 3 insertions, 3 deletions

diff --git a/examples/url_patterns.py b/examples/url_patterns.py
index 0fddb86..c948fef 100755
--- a/examples/url_patterns.py
+++ b/examples/url_patterns.py
@@ -5,13 +5,13 @@ An example of {ref}`url-patterns`
 """
 from datetime import timedelta
 
-from requests_cache import CachedSession
+from requests_cache import DO_NOT_CACHE, NEVER_EXPIRE, CachedSession
 
 default_expire_after = 60 * 60               # By default, cached responses expire in an hour
 urls_expire_after = {
     'httpbin.org/image': timedelta(days=7),  # Requests for this base URL will expire in a week
-    '*.fillmurray.com': -1,                  # Requests matching this pattern will never expire
-    '*.placeholder.com/*': 0,                # Requests matching this pattern will not be cached
+    '*.fillmurray.com': NEVER_EXPIRE,        # Requests matching this pattern will never expire
+    '*.placeholder.com/*': DO_NOT_CACHE,     # Requests matching this pattern will not be cached
 }
 urls = [
     'https://httpbin.org/get',               # Will expire in an hour