1{ 2 "topology_description": { 3 "type": "Unknown", 4 "servers": [] 5 }, 6 "operation": "read", 7 "read_preference": { 8 "mode": "SecondaryPreferred", 9 "tag_sets": [ 10 { 11 "data_center": "nyc" 12 } 13 ] 14 }, 15 "suitable_servers": [], 16 "in_latency_window": [] 17}