Where a DocumentSession does its work.
public enum ViewerThreading
Spec #33 story 54 (display lists built off the UI thread) and viewer capability 2 (time-sliced rendering).
kind:method, kind:property, kind:ctor. Press Esc to clear.AutomaticCooperative in the browser and WASI (one thread), otherwise Background.BackgroundBuilds display lists and renders tiles on thread-pool workers; the caller's thread only waits asynchronously.CooperativeWorks on the caller's thread and never blocks it: tiles render in slices of SliceBudget with a yield between slices, so a single-threaded host (Blazor WebAssembly) keeps drawing frames. A display-list build is not resumable and runs in one piece after a yield; it stops at its next cancellation check (every 1,024 operators) when cancelled.