code: @Nonnull
    @ReturnsMutableCopy
    public static byte [] encodeBytesToBytes (@Nonnull final byte [] source)
    {
      byte [] encoded;
      try
      {
        encoded = encodeBytesToBytes (source, 0, source.length, NO_OPTIONS);
      }
      catch (final IOException ex)
      {
        throw new IllegalStateException ("IOExceptions only come from GZipping, which is turned off", ex);
      }
      return encoded;
    }
docs: Similar to {@link #encodeBytes(byte[])} but returns a byte array instead of
  instantiating a String. This is more efficient if you're working with I/O
  streams and have large data sets to encode.
  
  @param source
  The data to convert
  @return The Base64-encoded data as a byte[] (of ASCII characters)
  @throws NullPointerException
  if source array is null
  @since 2.3.1