I have a service that has two different signals: If signal A changes, it will add a value to an array, if signal B changes it will remove the first value of the array. I am using a guard that manages what pages the user is allowed to visit depending on certain conditions, one being the queue that i just desribed. If the queue is not empty, i want to wait a certain time for my queue to be empty before i throw an error. How can i achieve this?