code: public long getUsedSpace() {
          long count = 0L;
          final int bufferSize = 1024 * 8;// Relatively big buffer (8MB); we're just reading
  
          final Map<ArchivePath, Node> contents = archive.getContent();
          final Collection<Node> nodes = contents.values();
          for (final Node node : nodes) {
              final Asset asset = node.getAsset();
              if (asset == null) {
                  continue; // Directory
              }
              final InputStream in = new BufferedInputStream(asset.openStream(), bufferSize);
              final byte[] buffer = new byte[bufferSize];
  
              int read = 0;
              try {
                  while ((read = in.read(buffer)) != -1) {
                      // Just count
                      count += read;
                  }
              } catch (final IOException ioe) {
                  throw new RuntimeException("Could not count size of archive " + this.archive.getName() + " at "
                      + asset.toString(), ioe);
              }
  
          }
  
          return count;
      }
docs: Iterates through the underlying archive, counting the size of each {@link Asset}, returning the fully-tallied
  count in bytes.
  
  @return