Write a workload of short-running reads (<1 second) with readPreference “primaryPreferred”. This should be run against a ReplSetTest with 2 nodes, where the primary is periodically shut down. Run this workload with the 4.2 version of pymongo to test without streamable isMaster (consider using a smaller client heartbeat frequency or a longer quiesce mode, in order to be robust to slow machines). Simulate 1 second of network latency between the driver and the primary using mongobridge. The test should disable retries in pymongo and assert that all commands succeed. This demonstrates that the need for retries is eliminated. Consider only running this test on variants that are not typically slow.