const mongoc_topology_description_t *td, const mongoc_read_prefs_t *prefs);
Determines if the topology has a readable server available. Servers are filtered by the given read preferences only if the driver is connected to a replica set, otherwise the read preferences are ignored. This function uses the driver’s current knowledge of the state of the MongoDB server or servers it is connected to; it does no I/O and it does not block.
True if there is a known server matching