docs: @Nonnull
    protected IFileItemHeaders getParsedHeaders (@Nonnull final String sHeaderPart)
    {
      final int nLen = sHeaderPart.length ();
      final FileItemHeaders aHeaders = createFileItemHeaders ();
      int nStart = 0;
      for (;;)
      {
        int nEnd = _parseEndOfLine (sHeaderPart, nStart);
        if (nStart == nEnd)
        {
          break;
        }
        final StringBuilder aHeader = new StringBuilder (sHeaderPart.substring (nStart, nEnd));
        nStart = nEnd + 2;
        while (nStart < nLen)
        {
          int nNonWs = nStart;
          while (nNonWs < nLen)
          {
            final char c = sHeaderPart.charAt (nNonWs);
            if (c != ' ' && c != '\t')
              break;
            ++nNonWs;
          }
          if (nNonWs == nStart)
            break;
  
          // Continuation line found
          nEnd = _parseEndOfLine (sHeaderPart, nNonWs);
          aHeader.append (' ').append (sHeaderPart.substring (nNonWs, nEnd));
  
          nStart = nEnd + 2;
        }
        _parseHeaderLine (aHeaders, aHeader.toString ());
      }
      return aHeaders;
    }