private SubscriptionManager createSubscriptionManager(
      final Vertx vertx,
      final TransactionPool transactionPool,
      final BlockchainQueries blockchainQueries) {
    final SubscriptionManager subscriptionManager =
        new SubscriptionManager(metricsSystem, blockchainQueries.getBlockchain());
    final PendingTransactionSubscriptionService pendingTransactions =
        new PendingTransactionSubscriptionService(subscriptionManager);
    final PendingTransactionDroppedSubscriptionService pendingTransactionsRemoved =
        new PendingTransactionDroppedSubscriptionService(subscriptionManager);
    transactionPool.subscribePendingTransactions(pendingTransactions);
    transactionPool.subscribeDroppedTransactions(pendingTransactionsRemoved);
    vertx.deployVerticle(subscriptionManager);

    return subscriptionManager;
  }
Gets fixed nodes. Visible for testing.

@param someFixedNodes the fixed nodes
@param moreFixedNodes nodes added to fixed nodes
@return the fixed and more nodes combined
app/src/main/java/org/hyperledger/besu/RunnerBuilder.java