Make documentation standalone and generalize examples

backend/scripts/bench_startup.py

@@ -1,13 +1,7 @@
-"""How long it takes to get a run started, which is the thing Kedro is slow at.
+"""Measure submission and completion latency against a running engine.
 
-A pipeline framework that boots the project per run pays that cost every time:
-``kedro run`` on a pipeline that does nothing takes about a second, and a sweep
-of five hundred configs therefore spends ten minutes doing nothing. Fluksio
-answers that by not booting anything — the engine is already up and its workers
-already have the code loaded, so submitting is one request.
-
-This measures that claim against a running stack, so it can be checked rather
-than asserted. Run it with the dev stack up::
+Uses a no-op flow to isolate scheduling overhead. Optionally compare it with
+an empty Kedro pipeline on the same machine. Run with the dev stack up::
 
     make bench-startup
     make bench-startup BENCH_ARGS="--runs 50 --kedro ../path/to/kedro/project"