curl --request POST \
  --url https://api.example.com/api/v1/files \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "bucket_id": "<string>",
  "content_type": "<string>",
  "filename": "<string>",
  "retention_period": 123,
  "size_bytes": 123
}
'

{
  "expires_at": "<string>",
  "file_uuid": "<string>",
  "status": "pending",
  "upload_url": "<string>"
}