[FEATURE REQUEST] pause server

[dcboy]

Is your feature request related to a problem? Please describe. I think I need to suspend a certain server node to receive and process tasks

Describe the solution you'd like asynq server pause asynq server unpause

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context When a certain node needs to be updated, I cannot directly kill the process. I must first suspend receiving tasks and wait for all current tasks to be executed before I can update.