@Override
  public void start() {
    vertx.eventBus().consumer(EVENTBUS_REMOVE_SUBSCRIPTIONS_ADDRESS, this::removeSubscriptions);
  }
The SubscriptionManager is responsible for managing subscriptions and sending messages to the
clients that have an active subscription.
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/websocket/subscription/SubscriptionManager.java