Automated grabbing timer with sleeps

Time how long the main thread has to wait for the grabber, or how long the grabber waits to be called, allowing automated sleeps (maybe use rolling weighted average?) to automatically try to grab frames so that they're ready just when the main processing finishes (optimal pipeline speed).

未指定任何檔案、測試或進入點。首先定位 grabber 和主執行緒影格處理流程，然後測量它們的等待時間並檢查現有的計時行為；完成這項工作需要達成一致的自動 sleep 策略，以提升管線速度。

由索引模型根據 Issue 內容生成。