`write` returns the written usize; now I wonder why rustc didn’t at
least produce a warning because the result was unused. Do we need to
add any flags to `rustSimple`?
Change-Id: If8d51d95c993dec6c92e46dbc82cd8cdd398f441
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3056
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>