1{
2  "topology_description": {
3    "type": "ReplicaSetNoPrimary",
4    "servers": [
5      {
6        "address": "b:27017",
7        "avg_rtt_ms": 5,
8        "type": "PossiblePrimary"
9      }
10    ]
11  },
12  "operation": "read",
13  "read_preference": {
14    "mode": "Nearest",
15    "tag_sets": [
16      {}
17    ]
18  },
19  "suitable_servers": [],
20  "in_latency_window": []
21}
22