{
    "heartbeatFrequencyMS": 25000,
    "in_latency_window": [
        {
            "address": "a:27017",
            "avg_rtt_ms": 5,
            "lastUpdateTime": 0,
            "lastWrite": {
                "lastWriteDate": {
                    "$numberLong": "1"
                }
            },
            "maxWireVersion": 5,
            "type": "RSPrimary"
        }
    ],
    "read_preference": {
        "maxStalenessSeconds": 150,
        "mode": "PrimaryPreferred"
    },
    "suitable_servers": [
        {
            "address": "a:27017",
            "avg_rtt_ms": 5,
            "lastUpdateTime": 0,
            "lastWrite": {
                "lastWriteDate": {
                    "$numberLong": "1"
                }
            },
            "maxWireVersion": 5,
            "type": "RSPrimary"
        }
    ],
    "topology_description": {
        "servers": [
            {
                "address": "a:27017",
                "avg_rtt_ms": 5,
                "lastUpdateTime": 0,
                "lastWrite": {
                    "lastWriteDate": {
                        "$numberLong": "1"
                    }
                },
                "maxWireVersion": 5,
                "type": "RSPrimary"
            },
            {
                "address": "b:27017",
                "avg_rtt_ms": 5,
                "lastUpdateTime": 0,
                "lastWrite": {
                    "lastWriteDate": {
                        "$numberLong": "1"
                    }
                },
                "maxWireVersion": 5,
                "type": "RSSecondary"
            }
        ],
        "type": "ReplicaSetWithPrimary"
    }
}