1topology_description: 2 type: ReplicaSetNoPrimary 3 servers: 4 - address: b:27017 5 avg_rtt_ms: 5 6 type: RSSecondary 7 tags: 8 data_center: nyc 9 - address: c:27017 10 avg_rtt_ms: 100 11 type: RSSecondary 12 tags: 13 data_center: nyc 14operation: read 15read_preference: 16 mode: SecondaryPreferred 17 tag_sets: 18 - data_center: sf 19suitable_servers: [] 20in_latency_window: []