Feature request from pareshe, posted on GitHub Nov 02, 2016
In checkout when click on Place order button take time around 13 seconds.
And when
Store > Configration > Sales > Sales Emails > General Settings > Asynchronous sending > Enable.
Then it take 7 seconds.
So it take to much time ,also send email from admin order view page. Also sending custom email using
observer "checkout_onepage_controller_success_action".
So email sending very slow.