{
  "schema": {
    "bsonType": "object",
    "required": [],
    "permission": {
      "read": true,
      "create": false,
      "update": "doc.user_id == auth.uid",
      "delete": false
    },
    "properties": {
      "_id": {
        "description": "ID，系统自动生成"
      },
      "is_read": {
        "bsonType": "bool",
        "defaultValue": false
      },
      "payload": {
        "state": {}
      }
    }
  },
  "index": []
}