renderScheduler property
Paces this page's first (UI-thread) interpret against every other page's, so a settling fast scroll can't fire them all in one frame. When set, the page registers its first render here instead of interpreting directly; the scheduler grants it a turn (see PdfPageRenderScheduler). Re-rasters of an already-interpreted page bypass it. Null falls back to renderHold.
Implementation
final PdfPageRenderScheduler? renderScheduler;