Resilient ReplicaSet for MongoDB

Hi,
I can see that currently we have to provide ReplicaSet Primary instance information to withMongoPool with createRsPool and ReplicaSetConfig. In case of MongoDB cloud installations, time to time, Primary instance can fail, hence secondaries re-elect new leader, in which case current connections will fail because our previous Primary, in best case scenario became a Secondary at best.

What I would like to do is, MongoDB driver already provides Primary function, which, when we provide a ReplicaHost list, it gives back current Primary... use this functionality to dynamically pick Primary, at least if connection error happens through out the pool usage.

If this is the case(I might be missing a functionality to cover this scenario already) and this approach is reasonable, then I can create a pull request with the enhanced functionality.

Start by reading the withMongoPool, createRsPool, and ReplicaSetConfig entry points, then check how the MongoDB driver's Primary function is currently exposed or used. Trace how connection errors propagate through pool usage and determine the expected behavior after replica-set re-election. Done means the project has a decided, tested approach for selecting the current primary.