{
  "topology_description": {
    "type": "ReplicaSetWithPrimary",
    "servers": [
      {
        "address": "a:27017",
        "avg_rtt_ms": 5,
        "type": "RSPrimary",
        "tags": {
          "data_center": "nyc"
        }
      },
      {
        "address": "b:27017",
        "avg_rtt_ms": 5,
        "type": "RSSecondary",
        "tags": {
          "data_center": "sf"
        }
      }
    ]
  },
  "operation": "read",
  "read_preference": {
    "mode": "SecondaryPreferred",
    "tag_sets": [
      {
        "data_center": "nyc"
      }
    ]
  },
  "suitable_servers": [
    {
      "address": "a:27017",
      "avg_rtt_ms": 5,
      "type": "RSPrimary",
      "tags": {
        "data_center": "nyc"
      }
    }
  ],
  "in_latency_window": [
    {
      "address": "a:27017",
      "avg_rtt_ms": 5,
      "type": "RSPrimary",
      "tags": {
        "data_center": "nyc"
      }
    }
  ]
}
