Count and distinct commands doesn't use cursors to return their response to users and mongos. Instead count and distinct use the RemoteCommandResponse struct to pass the result of the command in the "data" field. The "data" field is a single BSONObj which has a 16 MB limit. Count only returns one number, but distinct can return a large array, so we shouldn't return the query stats metrics in the "data" field because we might make the "data" field overflow the 16 MB limit. In RemoteCommandResponse we should add a new "metrics" field which will also be a BSONObj. This "metrics" field will hold all the query stats metrics. We will handle in future tickets actually using this "metrics" field but for right now we should add the "metrics" BSONObj to the RemoteCommandResponse so we can use this field in the future.