func (s *Arena) getVal(offset uint32, size uint16) (ret y.ValueStruct) {
	ret.Decode(s.buf[offset : offset+uint32(size)])
	return
}
func (s *Arena) getVal(offset uint32, size uint16) (ret y.ValueStruct) {
	ret.Decode(s.buf[offset : offset+uint32(size)])
	return
}
// getVal returns byte slice at offset. The given size should be just the value
// size and should NOT include the meta bytes.