将字节附加到golang中的字节缓冲区(Append byte to a byte buffer in golang)

I have a message byte Buffer and I would like to append a byte at the end of the Buffer

I tried to append like this:

append(message.Buf, 0xff)
first argument to append must be slice; have *bytes.Buffer

append(0xff,message.Buf)
first argument to append must be slice; have untyped number

How can I make the 0xff as a slice to append?