{
    "content": {
        "history_visibility": "world_readable"
    },
    "event_id": "$151957878235ricnD:localhost",
    "origin_server_ts": 1519578782195,
    "sender": "@example:localhost",
    "state_key": "",
    "type": "m.room.history_visibility",
    "unsigned": {
      "age": 1392989715
    }
}