newBuf := dst
	if len(dst) != len(p.readers) {
		newBuf = make([][]byte, len(p.readers))
	} else {
		for i := range newBuf {
			newBuf[i] = newBuf[i][:0]
		}
	}
	var newBufLK sync.RWMutex

	if p.offset+p.shardSize > p.shardFileSize {
		p.shardSize = p.shardFileSize - p.offset
	}
	if p.shardSize == 0 {
		return newBuf, nil
	}