For the POST request, _replicate, there are two modes, continuous and one-shot.
When "continuous == true", we respond asynchronous, that is, responding with OK right away indicating the request is received.
When "continuous == false", we pause and wait for the replication to complete (Stopped) and then respond. In this case, "ws:" may hang.
To repro, refers to
CBL-2209 REST _replicate hangs for one-shot mode