I would like to request functionality that keeps SDAM status and connections in between calls to mongoc_client_new_from_uri.

A PHP request is basically a request for an URL. Because PHP shares nothing among requests (not even the mongoc_client_t), the SDAM state is also not kept in between requests. Right now, PHPC only keeps connections in between PHP requests through persistent connections, a feature of PHP, where as HHVM does not do that either.

My request is that the CDRIVER has a mode (or something else), where SDAM states for equivalent mongoc_client_t structures are kept even though the mongoc_client_t gets destroyed and created. And, in addition to keeping the SDAM state around, also connections that are managed by the CDRIVER itself. This is what the legacy PHP driver does as well, as to optimise checking server states, and not reconnecting to i.e. every replicaset member on each request.