Currently, I think it's possible that the server will kill operations as part of stepdown due to heartbeats , and return a stale TopologyVersion because we don't call fulfillTopologyPromise (as part of _updateMemberStateFromTopologyCoordinator) until after we kill the operations.

This causes issues with retryable writes if a server returns a response with error InterruptedDueToReplStatechange with topologyVersion N (unchanged), and the driver will not know to mark the server as unknown before retrying the same write to the same node that is no longer a primary.