Function run_standalone 

pub fn run_standalone(
    config: &SchbenchConfig,
    run_secs: u64,
) -> StandaloneReport

Run the schbench engine standalone — host-side, no VM, no phases — for run_secs seconds and project the whole-run result into a StandaloneReport for the side-by-side validation against the reference schbench.

The run_secs window mirrors schbench’s -r <secs>: it is the benchmark’s own defined runtime — the workload behavior, like the per-request think-sleep in run — not a harness poll or synchronization wait. The engine itself stays stop-gated and event-driven; this wrapper is the only place a wall-clock timer drives it, bounding the benchmark window the way -r does upstream.

Non-phasic: phase_epoch is None, so the engine produces a single whole-run aggregate — the reference schbench has no phases, and the comparison is whole-run to whole-run.