curl --request POST \
  --url http://api.local.stratumn.com:3000/trace/{traceId}/link \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'body={
  "data": {},
  "actionKey": "<string>",
  "workflowId": "<string>",
  "groupLabel": "<string>"
}' \
  --form file_example='@example-file' \
  --form other_file_example='@example-file'

{
  "state": {}
}