method makeAttachment documentation in bbn\File\Pdf

function()
  {
			$pdf = $this->pdf->Output("", \Mpdf\Output\Destination::STRING_RETURN);
			return chunk_split(base64_encode($pdf));
		}
  }

BBN is a suite of PHP and JS libraries and VueJS components - all open-source! bbn.io, build applications, the quick way