{
  "heartbeatFrequencyMS": 25000,
  "topology_description": {
    "type": "ReplicaSetNoPrimary",
    "servers": [
      {
        "address": "a:27017",
        "type": "RSSecondary",
        "avg_rtt_ms": 5,
        "lastUpdateTime": 0,
        "maxWireVersion": 6,
        "lastWrite": {
          "lastWriteDate": {
            "$numberLong": "1000001"
          }
        }
      },
      {
        "address": "b:27017",
        "type": "RSSecondary",
        "avg_rtt_ms": 5,
        "lastUpdateTime": 0,
        "maxWireVersion": 6,
        "lastWrite": {
          "lastWriteDate": {
            "$numberLong": "1"
          }
        }
      }
    ]
  },
  "read_preference": {
    "mode": "PrimaryPreferred",
    "maxStalenessSeconds": 90
  },
  "suitable_servers": [
    {
      "address": "a:27017",
      "type": "RSSecondary",
      "avg_rtt_ms": 5,
      "lastUpdateTime": 0,
      "maxWireVersion": 6,
      "lastWrite": {
        "lastWriteDate": {
          "$numberLong": "1000001"
        }
      }
    }
  ],
  "in_latency_window": [
    {
      "address": "a:27017",
      "type": "RSSecondary",
      "avg_rtt_ms": 5,
      "lastUpdateTime": 0,
      "maxWireVersion": 6,
      "lastWrite": {
        "lastWriteDate": {
          "$numberLong": "1000001"
        }
      }
    }
  ]
}
