Function run_blocking 

pub fn run_blocking(
    executor: &BenchmarkExecutor,
    request: RunRequest,
    reporter: &mut dyn RunReporter,
    should_cancel: &dyn Fn() -> bool,
) -> Result<RunOutcome>

2026-09-26: Run to completion, pumping the executor’s channels. Blocks the calling thread; from async, use spawn_blocking.

should_cancel is polled once per drain; the first true cancels the run. Errors on invalid parameters, before the run starts, and when saving fails.