Is there a way to use the transactions in TCPDF when extending it with FPDI?

Question

I am using TCPDF with FPDI's bridge. The issue I'm having is that as soon as I use the startTransaction() I get the following error:

TCPDF ERROR: Cannot access protected property FPDI:$numpages / Undefined property: FPDI::$numpages

and the script ends (because of the die in the TCPDF::Error() method).

Here is the code I'm using:

$pdf = new FPDI();

// add a page
$pdf->AddPage();

$pdf->startTransaction();
$pdf->Cell(0, 0, 'blah blah blah');
$pdf->rollbackTransaction();

$pdf->Output( . time() . '.pdf', 'D');

If I change it to:

$pdf = new FPDI();

// add a page
$pdf->AddPage();

$pdf->Cell(0, 0, 'blah blah blah');

$pdf->Output( . time() . '.pdf', 'D');

it works fine.

Is there anyway to make them work together and use TCPDF's transactions?