轻量 Load Balancer

Design a lightweight load balancer with the following features: 1. Maintain a worker state machine represented by a priority queue to track worker load status; 2. Support dynamic scaling up and down of worker numbers; 3. Implement a time-bound complete code with necessary testing. Provide a performance analysis of the code, including the time and space complexity. Example Input add_worker(1) add_worker(2) assign_task() complete_task(1) remove_worker(1)