1topology_description:
2  type: ReplicaSetWithPrimary
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
14  - &1
15    address: a:27017
16    avg_rtt_ms: 26
17    type: RSPrimary
18    tags:
19      data_center: nyc
20operation: read
21read_preference:
22  mode: SecondaryPreferred
23  tag_sets:
24  - data_center: sf
25suitable_servers:
26- *1
27in_latency_window:
28- *1
29