Min-Heap Priority Queue Ordered by next_run

A scheduler needs to know which job fires next at any moment. Naive: scan all jobs, find min next_run. O(n) per tick.

Better: a min-heap keyed by next_run. The root is always the next job to fire. Insertion + removal are O(log n).

heap[0] = (2025-03-17T03:00:00Z, "backup-db")
heap[1] = (2025-03-17T05:00:00Z, "log-rotate")
heap[2] = (2025-03-17T09:15:00Z, "fetch-feeds")

Sleep until heap[0], fire it, recompute its next_run, push back.

Python: heapq. JS: write your own. Go: container/heap.

For deletion (job removed), keep a tombstones set and skip when popping; or use a more advanced structure (indexed heap).