[TODO] Eliminate Delay for Email Notifications

Currently the email notiftications from the forum are sent with a delay - sometimes 4 minutes, sometimes more than 10 minutes.
The goal is to eliminate this delay so that messages arrive quicker to the receivers.

I found only 2 relevant settings in the PHPBB administration board:

E-mail function name: mail
The e-mail function used to send mails through PHP.

E-mail package size: 30
This is the number of maximum e-mails sent out in one package. This setting is applied to the internal message queue; set this value to 0 if you have problems with non-delivered notification e-mails.