public Optional<Wei> getMaxFeePerGas() {
    return transactionWithMetadata.getTransaction().getMaxFeePerGas();
  }
Retrieves the maximum fee per gas of the transaction.

@return an Optional containing a Wei object representing the maximum fee per gas of the
    transaction, or an empty Optional if the transaction does not specify a maximum fee per
    gas.
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/graphql/internal/pojoadapter/TransactionAdapter.java