The monitor class, Mongo::SRV::Monitor, is under the capitalized SRV module name. The module name should be camel cased - Srv. Fortunately the class in question is a private class of the driver and hence we can rename the module without compatibility concerns.

Turns out there are two copies of SRV monitor in the driver - the one that is being used is under Cluster::SrvMonitor. This implementation is going to be moved over to Srv::Monitor.