docs: public static ImmutableMultimap<String, String> loadStringMultimap(CharSource multimapSource)
        throws IOException {
      final ImmutableMultimap.Builder<String, String> ret = ImmutableMultimap.builder();
  
      int count = 0;
      for (final String line : multimapSource.readLines()) {
        ++count;
        if (isCommentLine(line)) {
          continue;
        }
        final List<String> parts = multimapSplitter.splitToList(line);
        if (parts.isEmpty()) {
          continue;
        }
        ret.putAll(parts.get(0), skip(parts, 1));
      }
  
      return ret.build();
    }