Added the ability to select a method at runtime if so desired

roadmap/features/41-runtime-integrator-selection.md

@@ -1,6 +1,10 @@
 # Feature: Runtime Integrator Selection
 
-**Status**: proposed (2026-09-30)
+**Status**: completed (2026-09-30)
+
+Measured on the existing criterion benches, constants to methods: `bench_orbit`
+-0.73%, `bench_simple_1d` +0.42%, `bench_interpolation_1d` -0.09%. Criterion
+calls all three within its noise threshold, so the inlining claim below holds.
 
 ## Overview