Send email with large attachment

Hi 
I get the following error when sending email with attachments of big size.
We are using codeigniter 3.1.0

A PHP Error was encountered


Severity: Notice

Message: fwrite(): send of 8192 bytes failed with errno=11 Resource temporarily unavailable

Filename: libraries/Email.php

Line Number: 2207

Unfortunately, there can be a lot of reasons for a failing socket write. Reducing the number of bytes per fwrite could fix the problem, but I don't see a way to do that with CI, but I could be wrong.