Event loop scheduling improvement

Motivation

Think the following situation:

1. The browser event loop has a pending event that fires an event listener that schedules high-priority work to JSKit's executor.
2. But the current JSKit's executor loop does not yield its control to JS event loop until all enqueued works are done

• Even if some of them are low-priority

It resulted in the higher priority works planned to be enqueued to JSKit's executor are blocked by lower priority works that are already enqueued even though browser engine knows about the pending event.

Outcome

• Performance gain

Potential solution

Although yielding control to JS engine for every Swift job is not a realistic approach due to high overheads, but it's still considerable to yield control when certain time is spent for the current JSKit's executor loop.

從 Sources/JavaScriptEventLoop/JobQueue.swift 中的執行器迴圈開始，尤其關注連結的部分，並追蹤排入佇列的 Swift 工作如何執行，以及控制權如何返回瀏覽器事件迴圈。定義並評估一種排程方法，使其在執行器執行達到有界時長後讓出執行權；透過顯示較高優先級的待處理工作不再被低優先級工作阻塞，並測量對效能的影響，來證明該方法已完成。