docs: public void merge(VectorClock other) {
          for (Entry<String, Long> entry : other.replicaTimestamps.entrySet()) {
              final String replicaId = entry.getKey();
              final long mergingTimestamp = entry.getValue();
              final long localTimestamp = replicaTimestamps.containsKey(replicaId)
                      ? replicaTimestamps.get(replicaId)
                      : Long.MIN_VALUE;
              replicaTimestamps.put(replicaId, Math.max(localTimestamp, mergingTimestamp));
          }
      }