The new method accepts the usual parameters (method, endpoint, params, entity and headers) plus a response listener and an async response consumer. Shortcut methods are also added that don't require params, entity and the async response consumer optional.
There are a few relevant api changes as a consequence of the move to async client that affect sync methods:
- Response doesn't implement Closeable anymore, responses don't need to be closed
- performRequest throws Exception rather than just IOException, as that is the the exception that we get from the FutureCallback#failed method in the async http client
- ssl configuration is a bit simpler, one only needs to call setSSLStrategy from a custom HttpClientConfigCallback, that doesn't end up overridng any other default around connection pooling (it used to happen with the sync client and make ssl configuration more complex)
Relates to #19055