Prune commentary and stale Rust port notes

examples/bench_images.rs

@@ -1,27 +1,3 @@
-//! (d) of IRIS_TODO.md's "Benchmarks" item: 1,000 image rows, checking that
-//! standalone-image bind-group *creation* -- a real `wgpu` resource, unlike
-//! the counters in `benches/message_lazy_span.rs` -- goes to zero once every
-//! image has loaded. This needs an actual `wgpu` device (`GpuTextures`,
-//! `UiRenderNode`), so unlike the rest of the suite it cannot run as a
-//! plain binary; run it through `iris/run-headless.sh bench_images`, which
-//! gives it a real (headless, GPU-accelerated) compositor and surface. See
-//! `run-bench.sh` for the wrapper that greps its output into one line.
-//!
-//! Each `RedrawRequested` prints the frame number and
-//! `UiRenderNode::take_image_bind_group_creates()` for that frame, then
-//! requests another redraw (nothing else marks the scene dirty, so without
-//! this the app would only ever draw once). The first frame is expected to
-//! report 1,000 (one create per image, on first load); the steady state
-//! IRIS_TODO.md asks this scenario to prove is every frame after settling
-//! down to 0.
-//!
-//! After `SETTLE_FRAMES` it appends one *new* image row (a transcript
-//! receiving one more message) and keeps counting -- a chat transcript's
-//! real access pattern is "one more image arrives," not "reload the whole
-//! list," so the steady-state question that actually matters is the
-//! *incremental* cost of that one append, not just whether an untouched
-//! scene costs zero. It exits after `FRAMES`.
-
 use iris::prelude::*;
 
 const ROWS: usize = 1000;