Redis::throttle() rate limiting explain release method()

release(10) means that the job will be released 10 seconds later. It's just a delay parameter.

You can find it here in the code: https://github.com/laravel/framework/blob/56a58e0fa3d845bb992d7c64ac9bb6d0c24b745a/src/Illuminate/Queue/Jobs/RedisJob.php#L93

For each implementation this method is different. You can also see this method for the DatabaseJob for example: https://github.com/laravel/framework/blob/56a58e0fa3d845bb992d7c64ac9bb6d0c24b745a/src/Illuminate/Queue/Jobs/DatabaseJob.php#L50

It's a bit harder to search for this, since it has multiple traits and interfaces ;)

Quick question, how does this work with multiple servers interacting with one queue