There're two issues

1. The mongo client does not reflect on client options `srv_max_hosts` unless we append on URI. (e.g. `?srvMaxHosts=3`)
   1. the `uri_options` does not contains `srv_max_hosts`
2. Even we use `?srvMaxHosts=3` the cluster monitoring keep scanning the cluster without `srv_max_hosts` options (third argument variable of resolver#get_records)