curl --request GET \
  --url https://{gatewayBaseURL}/batches/{id} \
  --header 'Authorization: Bearer <token>'

{
  "id": "<string>",
  "object": "<string>",
  "endpoint": "<string>",
  "input_file_id": "<string>",
  "completion_window": "<string>",
  "status": "<string>",
  "output_file_id": "<string>",
  "error_file_id": "<string>",
  "created_at": 123,
  "in_progress_at": 123,
  "expires_at": 123,
  "finalizing_at": 123,
  "completed_at": 123,
  "failed_at": 123,
  "expired_at": 123,
  "cancelling_at": 123,
  "cancelled_at": 123,
  "request_counts": {
    "total": 123,
    "completed": 123,
    "failed": 123
  },
  "errors": "<unknown>",
  "metadata": "<unknown>"
}