[Bug] Mass-PM takes too much memory

[fionera]

Describe the bug
When you have a lot of Users, the Mass-PM feature requires a very high memory limit and times out.

To Reproduce
Steps to reproduce the behavior:

1. Have 8000 users
2. Send a Mass Message
3. See error

Expected behavior
The messages should be send.

UNIT3D (please complete the following information):

• UNIT3D Version: master
• Laravel Version: -
• PHP Version: 7.4
• Database Driver & Version: -
• Web Server Driver & Version: Nginx
• OS Driver and Version: Ubuntu 20.04

Desktop (please complete the following information):

• OS: -
• Browser: -
• Version: -

Additional context

Possible Fix?
The Messages should be send in the Background in batches and not as a single Call.

[HDVinnie]

@fionera im not able to replicate this. The mass pm function already loops through all users and dispatches a queued job.

        foreach ($users as $user) {
            $this->dispatch(new ProcessMassPM(self::SENDER_ID, $user->id, $subject, $message));
        }

It wouldn't send all 8000 at once unless using the sync queue driver. What do you suggest?

[HDVinnie]

@fionera be sure to test the latest PR. #1451

I am seeing no memory/timeout issues sending a mass pm to 18,500 users.