pub fn init_logging()Expand description
Install the harness’s logger backend once, for the whole test process.
Called by Ctx::headless, so a test that builds a context logs without
asking. Tests that never build a context — the ECS ones — call this
directly if they log.
RUST_LOG picks the level natively; without it the default is warn.
A process holds one logger, so repeated calls are no-ops — and a test that
installed a backend of its own first keeps it.