解码收件人电子邮件地址mimeDecode.php

I am working with the https://github.com/stuporglue/mailreader script which requires http://pear.php.net/package/Mail_mimeDecode/.

The script works great, however, I can't find the method to get the recipient's email address.

This is how I get the sender:

 $this->from = $this->decoded->headers['from'];

For the recipient I tried:

$this->to = $this->decoded->headers['to']; (seemed obvious)

$to_email = $this->to;

but $to_email is empty.