text: {
    "topology_description": {
      "type": "ReplicaSetWithPrimary",
      "servers": [
        {
          "address": "a:27017",
          "type": "RSPrimary",
          "avg_rtt_ms": 5,
          "lastUpdateTime": 0,
          "maxWireVersion": 5,
          "lastWrite": {
            "lastWriteDate": {
              "$numberLong": "1"
            }
          }
        },
        {
          "address": "b:27017",
          "type": "RSSecondary",
          "avg_rtt_ms": 5,
          "lastUpdateTime": 0,
          "maxWireVersion": 5,
          "lastWrite": {
            "lastWriteDate": {
              "$numberLong": "1"
            }
          }
        }
      ]
    },
    "read_preference": {
      "maxStalenessSeconds": 120
    },
    "error": true
  }
  