Adds the full `AsyncConfig` class to `ldclient/async_config.py`,
building on the previously-merged `AsyncBigSegmentsConfig` seed (#462).
This is a stacked-PR slice of the async Python SDK epic (SDK-60),
unblocked now that #463 merged `AsyncHook`/`AsyncPlugin`.

`AsyncConfig` mirrors the sync `Config` surface for the async client:
base/events/stream URIs, streaming vs. polling, event buffering, private
attributes, big segments, hooks, plugins, HTTP config, application
metadata, and the experimental data system config. The concrete
`AsyncEventProcessor` is imported only under `TYPE_CHECKING` to keep
aiohttp out of the runtime import graph.

This is self-contained and reviewable on its own. It unblocks the
upcoming async FDv1 polling (PR 7) and async event processor (PR 8),
both of which import the full `AsyncConfig`.

The public `AsyncConfig` (and `AsyncBigSegmentsConfig`) carry an
experimental `.. caution::` note — this API may change without notice
and is not yet production-ready.

Tracked internally: SDK-2768

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Large new experimental configuration surface touches networking,
events, and data-source wiring for the async client, though behavior is
additive and sync Config changes are limited to shared constants.
> 
> **Overview**
> Adds **`AsyncConfig`** in `ldclient/async_config.py` so
**`AsyncLDClient`** can be configured with the same knobs as sync
**`Config`**: endpoints, streaming/polling, events, privacy, big
segments, hooks/plugins, HTTP, payload filtering, and experimental
data-system settings. It wires in **`AsyncFeatureStore`** (default
**`AsyncInMemoryFeatureStore`**), **`AsyncHook`** / **`AsyncPlugin`**,
and factory hooks for **`AsyncUpdateProcessor`** and
**`AsyncEventProcessor`**, with experimental **`.. caution::`** on the
public API.
> 
> Sync **`Config`** now reuses shared **`DEFAULT_*_URI`** constants
instead of inline URL literals.
> 
> **`interfaces.py`** gains experimental **`AsyncUpdateProcessor`** and
**`AsyncEventProcessor`** (async **`stop`**, plus **`flush_and_wait`**
on the event processor) for upcoming async polling and event delivery.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
3303a25. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

🤖 I have created a release *beep* *boop*
---


##
[9.17.0](9.16.1...9.17.0)
(2026-08-28)


### Features

* Add async big segment store manager and async Redis adapter
([#462](#462))
([aa492d2](aa492d2))
* Add async DynamoDB persistent feature store
([#490](#490))
([cb010df](cb010df))
* Add async event processor
([ec7c113](ec7c113))
* Add async event processor
([#472](#472))
([ec7c113](ec7c113))
* Add async FDv1 polling data source and feature requester
([#475](#475))
([cca37a8](cca37a8))
* Add async FDv1 streaming and data source status tracking
([#464](#464))
([4bf7067](4bf7067))
* Add async FDv2 data sources
([#485](#485))
([5da1515](5da1515))
* Add async FDv2 data system
([#486](#486))
([6a70132](6a70132))
* Add async hook, plugin, and flag tracker
([#463](#463))
([686a70a](686a70a))
* Add async migration support
([#470](#470))
([577d51e](577d51e))
* Add async persistent feature store foundation and Redis adapter
([f9c76ee](f9c76ee))
* Add AsyncConfig for the async SDK client
([#471](#471))
([0587a78](0587a78))
* Add AsyncLDClient with FDv1 data system and public API
([#480](#480))
([fd041a5](fd041a5))
* Add Config.with_wrapper_information
([#501](#501))
([8a98583](8a98583))
* Add environment ID support for hooks.
([#484](#484))
([49e809f](49e809f))
* Add read-only store views and async persistence foundation for the
data system
([#503](#503))
([0eb61fa](0eb61fa))


### Bug Fixes

* Allow tombstones without a key property
([#502](#502))
([5f44e61](5f44e61))
* Escape attribute names reported in redactedAttributes
([#505](#505))
([90059cb](90059cb))
* Prevent a persistent-store outage from throwing in the sync FDv2
evaluation
([#506](#506))
([467da53](467da53))
* Return empty prerequisites for a flag that fails to evaluate in
all_flags_state
([#483](#483))
([73e9b07](73e9b07))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Overview**
> **Release Please** bumps the package from **9.16.1** to **9.17.0** in
`pyproject.toml`, `ldclient/version.py`,
`.release-please-manifest.json`, and the provenance example in
`PROVENANCE.md`.
> 
> `CHANGELOG.md` gains a new **9.17.0** (2026-08-28) section that
records what ships in this minor release: a broad **async** surface
(`AsyncLDClient`, `AsyncConfig`, async FDv1/FDv2 data systems, event
processor, hooks/plugins, migration, and Redis/DynamoDB persistent
stores plus big-segment async support), plus sync improvements
(`Config.with_wrapper_information`, hook environment ID, read-only store
views) and bug fixes (tombstones, `redactedAttributes` escaping, FDv2
persistent-store resilience, `all_flags_state` prerequisites).
> 
> No application logic changes appear in this diff—only version metadata
and release notes.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
f225e46. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>