code: func (b *Buffer) AppendBytes(data []byte) {
  	for len(data) > 0 {
  		if cap(b.Buf) == len(b.Buf) { // EnsureSpace won't be inlined.
  			b.EnsureSpace(1)
  		}
  
  		sz := cap(b.Buf) - len(b.Buf)
  		if sz > len(data) {
  			sz = len(data)
  		}
  
  		b.Buf = append(b.Buf, data[:sz]...)
  		data = data[sz:]
  	}
  }
docs: // AppendBytes appends a byte slice to buffer.