1topology_description: 2 type: Single 3 servers: 4 - &1 5 address: a:27017 6 avg_rtt_ms: 5 7 type: Standalone 8 tags: 9 data_center: dc 10operation: read 11read_preference: 12 mode: SecondaryPreferred 13 tag_sets: 14 - data_center: nyc 15suitable_servers: 16- *1 17in_latency_window: 18- *1