fbuf.go
func (b *Float64RingBuf) ReadWithoutAdvance(p []float64) (n int, err error) {
	return b.readAndMaybeAdvance(p, false)
}
func (b *Float64RingBuf) ReadWithoutAdvance(p []float64) (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.