Specifically, I'd like the following to be exposed in serverStatus (this is from the design document):

getDefaultRWConcern
 defaults:
{ readConcern: \{ ... }, // empty obj if not set
 writeConcern: { ... } // empty obj if not set
} 

This is for metrics, to see how many people are using it once it launches.

My assumptions: If a user does not configure it, there will be no object. If a user does configure it, even to the default value, it will exist. (these are assumptions, not requirements, so if you envision something different let's talk)

Example:

user sets readConcern but not writeConcern:

defaultRWConcern: