curl --request PATCH \
  --url https://general-runtime.voiceflow.com/state/user/{userID}/variables \
  --header 'Content-Type: application/json' \
  --header 'authorization: <api-key>' \
  --header 'projectID: <projectid>' \
  --data '{}'

{
  "stack": [
    {
      "diagramID": "<string>",
      "storage": {},
      "variables": {},
      "nodeID": "<string>",
      "name": null,
      "commands": [
        {
          "type": "<string>"
        }
      ],
      "dynamicCommands": {}
    }
  ],
  "variables": {},
  "storage": {},
  "turn": {}
}