* BaseClient and AsyncClient
* Introduce 'httpx.Client'
* Top level API -> sync
* Top level API -> sync
* Add WSGI support, drop deprecated imports
* Wire up timeouts to urllib3
* Wire up pool_limits
* Add urllib3 proxy support
* Pull #734 into sync Client
* Update AsyncClient docstring
* Simpler WSGI implementation
* Set body=None when no content
* Wrap urllib3 connection/read exceptions
* Support thread-pooled dispatch
* Add ConcurrencyBackend.run
* Initial work towards support byte-iterators on sync request data
* Test case for byte iterator content
* byte iterator support for RequestData
* Add BaseResponse
* Bridge sync/async data in SyncResponse
* Add BaseClient
* SyncResponse -> Response
* Tweaking type annotation
* Distinct classes for Request, AsyncRequest
* Tweak is_streaming, content in BaseRequest
* Stream handling moves to client
* Handle mediating to AsyncResponse from a standard sync Dispatcher class
* Working on thread-pooled dispatcher
* Support threaded dispatch, inc. streaming requests/responses
* Increase test coverage
* Coverage and tweaks
* Include Accept and User-Agent headers by default