curl --request POST \
  --url https://example.com/api/scan/v0/backfilling/import-updates \
  --header 'Content-Type: application/json' \
  --data '
{
  "migration_id": 123,
  "after_update_id": "<string>",
  "limit": 123
}
'

{
  "transactions": [
    {
      "update_id": "<string>",
      "migration_id": 123,
      "workflow_id": "<string>",
      "record_time": "<string>",
      "synchronizer_id": "<string>",
      "effective_at": "<string>",
      "offset": "<string>",
      "root_event_ids": [
        "<string>"
      ],
      "events_by_id": {},
      "external_transaction_hash": "<string>"
    }
  ]
}