code: public ImportSection loadImportSection() throws IOException {
          Optional<ImportSection> idata = maybeLoadImportSection();
          return (ImportSection) getOrThrow(idata,
                  "unable to load import section");
      }
docs: Loads all bytes and information of the import section. The file on disk
  is read to fetch the information.
  
  @return the import section
  @throws IOException
  if unable to read the file
  @throws IllegalStateException
  if unable to load section