tr.curr = &sparseFileReader{tr.curr, sph, 0}
	}
	return err
}

// readGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers.
// If they are found, then this function reads the sparse map and returns it.
// This assumes that 0.0 headers have already been converted to 0.1 headers
// by the PAX header parsing logic.
func (tr *Reader) readGNUSparsePAXHeaders(hdr *Header) (sparseDatas, error) {

}

// startReader will start a reader that accepts input from r.input.
// Input should be root -> object input. Each root indicates a record.
// If r.input is closed, it is assumed that no more input will come.
// When this function returns r.readerWg will be decremented and r.decoded will be closed.
// On errors, r.err will be set. This should only be accessed after r.decoded has been closed.
func (r *Reader) startReader() {
	defer r.onReaderExit()