C++ API takes a transaction argument without allocating it

Transaction &
utils::internal::getTransaction(TSHttpTxn ats_txn_handle)
{
  Transaction *transaction = static_cast<Transaction *>(TSHttpTxnArgGet(ats_txn_handle, TRANSACTION_STORAGE_INDEX));
  if (!transaction) {
    transaction = new Transaction(static_cast<void *>(ats_txn_handle));
    LOG_DEBUG("Created new transaction object at %p for ats pointer %p", transaction, ats_txn_handle);
    TSHttpTxnArgSet(ats_txn_handle, TRANSACTION_STORAGE_INDEX, transaction);
  }
  return *transaction;
}