@Override
  public List<Transaction> getPriorityTransactions() {
    return pendingTransactions.values().stream()
        .filter(PendingTransaction::hasPriority)
        .map(PendingTransaction::getTransaction)
        .collect(Collectors.toList());
  }
Holds the current set of pending transactions with the ability to iterate them based on priority
for mining or look-up by hash.

<p>This class is safe for use across multiple threads.
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/sorter/AbstractPendingTransactionsSorter.java