curl --request POST \
  --url https://video.bunnycdn.com/library/{libraryId}/videos/{videoId}/captions/{srclang} \
  --header 'AccessKey: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "srclang": "<string>",
  "label": "<string>",
  "captionsFile": "<string>"
}
'

{
  "success": true,
  "message": "<string>",
  "statusCode": 123
}