json_schema: {
      "additionalProperties": false,
      "description": "A user_engagement GA4 event.",
      "properties": {
          "engagement_time_msec": {
              "description": "The time in milliseconds that the user is engaged.",
              "minimum": 0,
              "type": [
                  "integer",
                  "null"
              ]
          }
      },
      "self": {
          "format": "jsonschema",
          "name": "user_engagement",
          "vendor": "com.google.ga4",
          "version": "1-0-0"
      },
      "type": "object"
  }