public void add(final BftEvent event) {

    // Don't queue events other than block timer expiry, until we know we can process them
    if (isStarted() || event.getType() == BftEvents.Type.BLOCK_TIMER_EXPIRY) {
      if (queue.size() > messageQueueLimit) {
        LOG.warn("Queue size exceeded trying to add new bft event {}", event);
      } else {
        queue.add(event);
      }
    }
  }
Put an Bft event onto the queue. Note: the event queue must be started before an event will be
queued for processing. Events received before the queue is started will be discarded.

@param event Provided bft event
consensus/common/src/main/java/org/hyperledger/besu/consensus/common/bft/BftEventQueue.java