{
    "in_latency_window": [
        {
            "address": "b:27017",
            "avg_rtt_ms": 5,
            "tags": {
                "data_center": "nyc",
                "rack": "one"
            },
            "type": "RSSecondary"
        }
    ],
    "operation": "read",
    "read_preference": {
        "mode": "Secondary",
        "tag_sets": [
            {
                "data_center": "nyc",
                "rack": "one"
            },
            {
                "other_tag": "doesntexist"
            }
        ]
    },
    "suitable_servers": [
        {
            "address": "b:27017",
            "avg_rtt_ms": 5,
            "tags": {
                "data_center": "nyc",
                "rack": "one"
            },
            "type": "RSSecondary"
        }
    ],
    "topology_description": {
        "servers": [
            {
                "address": "b:27017",
                "avg_rtt_ms": 5,
                "tags": {
                    "data_center": "nyc",
                    "rack": "one"
                },
                "type": "RSSecondary"
            },
            {
                "address": "c:27017",
                "avg_rtt_ms": 5,
                "tags": {
                    "data_center": "sf",
                    "rack": "two"
                },
                "type": "RSSecondary"
            }
        ],
        "type": "ReplicaSetNoPrimary"
    }
}