swiftmailer text / plain line breaks？

I am trying to send a message using PHPs mail library called Swiftmailer. The problem is that the text is rendered without line breaks and I can't really see the reason for that. I've tried reading the mail using gmail and yahoo.

The code:

// [..] bla bla
$message->setBody("a
b", 'text/plain')

HTML doesn't obey line breaks (they're treated as spaces). You need to use <br /> tags instead. If you're filling in plaintext dynamically, you can use PHP's nl2br() to do this for you.

You can use PHP_EOL Example:

    ->setBody('Hi Sir/Mam,'.PHP_EOL.'Here is my message.')