atomic_rbuf.go
func (b *AtomicFixedSizeRingBuf) ReadWithoutAdvance(p []byte) (n int, err error) {
	return b.ReadAndMaybeAdvance(p, false)
}
func (b *AtomicFixedSizeRingBuf) ReadWithoutAdvance(p []byte) (n int, err error) {
	return b.ReadAndMaybeAdvance(p, false)
}
// ReadWithoutAdvance(): if you want to Read the data and leave
// it in the buffer, so as to peek ahead for example.