func (b *bufioR) compact() {
	if b.r > 0 {
		copy(b.buf, b.buf[b.r:b.w])
		b.w -= b.r
		b.r = 0
	}
}
// compact moves the unread chunk to the beginning of the buffer
compact moves the unread chunk to the beginning of the buffer
// compact moves the unread chunk to the beginning of the buffer
func (b *bufioR) compact() {
	if b.r > 0 {
		copy(b.buf, b.buf[b.r:b.w])
		b.w -= b.r
		b.r = 0
	}
}
func ( b * bufioR ) compact ( ) { if b . r > 0 { copy ( b . buf , b . buf [ b . r : b . w ] ) b . w -= b . r b . r = 0 } }
compact moves the unread chunk to the beginning of the buffer
compact moves the unread chunk to the beginning of the buffer