protected static MailFormatHelper::wrapMailLine(&$line, $key, $values)
Wraps words on a single line.
Callback for array_walk() within \Drupal\Core\Mail\MailFormatHelper::wrapMail().
Note that we are skipping MIME content header lines, because attached files, especially applications, could have long MIME types or long filenames which result in line length longer than the 77 characters limit and wrapping that line will break the email format. For instance, the attached file hello_drupal.docx