Empty attachment using PHP mailer - php

Question

I am trying to send a mail with a attachment using PHP. When I send the mail I am recieving it with a empty attachment (the attachment file size = 0 bytes). The filepath that I am using is correct.
Does someone know what is wrong with my script. Why am I recieving an empty attachment?
Here is my script:
$to = $destination;
$from = 'test#test.test';
$fromName = 'Test';
$subject = $subject;
$file = "./image-based-pdf-sample.pdf";
$htmlContent = $content;
$headers = "From: $fromName"." <".$from.">";
$semi_rand = md5(time());
$mime_boundary = "==Multipart_Boundary_x{$semi_rand}x";
$headers .= "\nMIME-Version: 1.0\n" . "Content-Type: multipart/mixed;\n" . " boundary=\"{$mime_boundary}\"";
$message = "--{$mime_boundary}\n" . "Content-Type: text/html; charset=\"UTF-8\"\n" .
"Content-Transfer-Encoding: 7bit\r\n" . $htmlContent . "\r\n";
$message .= "--{$mime_boundary}\n";
$fp = #fopen($file,"rb");
$data = #fread($fp,filesize($file));
#fclose($fp);
$data = chunk_split(base64_encode($data));
$message .= "Content-Type: application/octet-stream; name=\"".basename($file)."\"\n" .
"Content-Description: ".basename($file)."\n" .
"Content-Disposition: attachment;\n" . " filename=\"".basename($file)."\"; size=".filesize($file).";\n" .
"Content-Transfer-Encoding: base64\r\n" . $data . "\r\n";
$message .= "--{$mime_boundary}--";
$returnpath = "-f" . $from;
$mail = #mail($to, $subject, $message, $headers, $returnpath);
echo $mail?"<h1>Success</h1>":"<h1>Error</h1>";