code: public void insertOrMerge(Data... toPersist) throws DRUMSException, InterruptedException {
          try {
              bucketContainer.addToCache(toPersist);
          } catch (BucketContainerException ex) {
              // This exception should never be thrown because the hash function should map all keys to a bucket.
              throw new DRUMSException(ex);
          }
      }
docs: Adds or merges the given data. If all memory buckets are full, this method is blocking the calling thread. <br>
  <br>
  A merge calls the method {@link Data#merge(AbstractKVStorable)}.
  
  @param toPersist
  data to insert or update
  @throws DRUMSException
  if an unexpected error occurs
  @throws InterruptedException
  if the call blocks and the current thread is interrupted