code: public BatcherBuilder sizeBound(int size) {
          checkState(this.maxSize == UNSET_INT, "Max size already set to %s", this.maxSize);
          checkArgument(size > 0, "Required to have a size bound greater than 0");
          this.maxSize = size;
          return this;
      }
docs: Add a max size component for a batcher.  If specified a batcher will call the {@link BatchListener}
  as soon as the size bound is reached.