v1.2.0

• Payload handlers are now stateless: the request model is built per-call instead of being stored on the handler, so shared/singleton handlers are safe under concurrent (including async) requests.
• Handler req_model, resp_model and dry can now be declared as class attributes, in addition to __init__ arguments (backward compatible).
• Added sync/async type markers _Sync, _Async and the _Mode TypeVar, enabling correctly-typed async clients through overloads.
• APIClient now dispatches requests via __getattr__ instead of __getattribute__ (faster; only triggered on an attribute miss).
• The httpx client is now created lazily and can be closed: added close()/aclose() and (async) context-manager support. Importing a client no longer opens connections.
• Request timeout is now configurable (default: 10s).
• Non-JSON or empty response bodies no longer raise JSONDecodeError; APIResponse now decodes defensively.
• PayloadBaseModel.from_args now raises on duplicate or excess positional arguments.

Full Changelog: v1.1.1...v1.2.0