@Override
  protected String internalLogStats() {
    if (orderByFee.isEmpty()) {
      return "GasPrice Prioritized: Empty";
    }

    final PendingTransaction highest = orderByFee.last();
    final PendingTransaction lowest = orderByFee.first();

    return "GasPrice Prioritized: "
        + "count: "
        + pendingTransactions.size()
        + ", space used: "
        + spaceUsed
        + ", unique senders: "
        + txsBySender.size()
        + ", highest priority tx: [score: "
        + highest.getScore()
        + ", gas price: "
        + highest.getTransaction().getGasPrice().get().toHumanReadableString()
        + ", hash: "
        + highest.getHash()
        + "], lowest priority tx: [score: "
        + lowest.getScore()
        + ", gas price: "
        + lowest.getTransaction().getGasPrice().get().toHumanReadableString()
        + ", hash: "
        + lowest.getHash()
        + "]";
  }
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/layered/GasPricePrioritizedTransactions.java