Unit tests rely on mockito to mock the internal HttpClient instance. No http request is performed, we only simulate interaction between RestClient and its internal HttpClient.
Use sun HttpServer instead and disable forbidden-apis for test classes. It turns out to be more flexible than okhttp as it allows get & delete with body.
Create a new subproject called client-sniffer that contains the o.e.client.sniff package. Since it is going to go to a separate jar, due to its additional functionalities and dependency on jackson, it makes sense to have it as a separate project that depends on client. This way we make sure that client doesn't depend on it etc.