func (b *AtomicFixedSizeRingBuf) Adopt(me []byte) {
	b.tex.Lock()
	defer b.tex.Unlock()

	n := len(me)
	if n > b.N {
		b.A[0] = me
		b.A[1] = make([]byte, n, n)
		b.N = n
		b.Use = 0
		b.Beg = 0
		b.readable = n
	} else {
		// we already have a larger buffer, reuse it.
		copy(b.A[0], me)
		b.Use = 0
		b.Beg = 0
		b.readable = n
	}
}
func (b *AtomicFixedSizeRingBuf) Adopt(me []byte) {
	b.tex.Lock()
	defer b.tex.Unlock()

	n := len(me)
	if n > b.N {
		b.A[0] = me
		b.A[1] = make([]byte, n, n)
		b.N = n
		b.Use = 0
		b.Beg = 0
		b.readable = n
	} else {
		// we already have a larger buffer, reuse it.
		copy(b.A[0], me)
		b.Use = 0
		b.Beg = 0
		b.readable = n
	}
}
// Adopt(): non-standard.
//
// For efficiency's sake, (possibly) take ownership of
// already allocated slice offered in me.
//
// If me is large we will adopt it, and we will potentially then
// write to the me buffer.
// If we already have a bigger buffer, copy me into the existing
// buffer instead.
//
// Side-effect: may change b.Use, among other internal state changes.
//