public TransactionSelectionResults buildTransactionListForBlock() {
    timeLimitedSelection();
    LOG.atTrace()
        .setMessage("Transaction selection result {}")
        .addArgument(transactionSelectionResults::toTraceLog)
        .log();
    return transactionSelectionResults;
  }
Builds a list of transactions for a block by iterating over all transactions in the
PendingTransactions pool. This operation can be long-running and, if executed in a separate
thread, can be cancelled via the isCancelled supplier, which would result in a
CancellationException.

@return The {@code TransactionSelectionResults} containing the results of transaction
    evaluation.
ethereum/blockcreation/src/main/java/org/hyperledger/besu/ethereum/blockcreation/txselection/BlockTransactionSelector.java