type BytePoolCap struct {
	c    chan []byte
	w    int
	wcap int
}

// NewBytePoolCap creates a new BytePool bounded to the given maxSize, with new
// byte arrays sized based on width.
func NewBytePoolCap(maxSize uint64, width int, capwidth int) (bp *BytePoolCap) {
	if capwidth > 0 && capwidth < 64 {
		panic("buffer capped with smaller than 64 bytes is not supported")
	}
	if capwidth > 0 && width > capwidth {