code: public static final void writeEncodeQuotedPrintableByte (final int b,
                                                             @Nonnull final OutputStream aOS) throws IOException
    {
      final char cHigh = StringHelper.getHexCharUpperCase ((b >> 4) & 0xF);
      final char cLow = StringHelper.getHexCharUpperCase (b & 0xF);
      aOS.write (ESCAPE_CHAR);
      aOS.write (cHigh);
      aOS.write (cLow);
    }
docs: Encodes byte into its quoted-printable representation.
  
  @param b
  byte to encode
  @param aOS
  the output stream to write to
  @throws IOException
  In case writing to the OutputStream failed