curl --request POST \
  --url https://api.klavis.ai/sandbox/gmail/{sandbox_id}/initialize \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "messages": [
    {
      "subject": "<string>",
      "to": "<string>",
      "body": "<string>",
      "cc": "<string>",
      "bcc": "<string>",
      "from": "<string>",
      "reply_to": "<string>",
      "labels": [
        "<string>"
      ]
    }
  ],
  "drafts": [
    {
      "subject": "<string>",
      "to": "<string>",
      "body": "<string>",
      "cc": "<string>",
      "bcc": "<string>",
      "from": "<string>",
      "reply_to": "<string>"
    }
  ]
}
'

{
  "sandbox_id": "<string>",
  "status": "idle",
  "message": "<string>",
  "records_created": {}
}