func NewReader(r io.Reader, filter Filter) *Reader {
	return &Reader{
		pbr:    pbutil.NewReader(r),
		filter: filter,
	}
}
func NewReader(r io.Reader, filter Filter) *Reader {
	return &Reader{
		pbr:    pbutil.NewReader(r),
		filter: filter,
	}
}
// NewReader creates a new hashtree reader.