When you fire a machine gun at night, it’s difficult to see where your bullets are going. Even when the target is in plain sight, hitting a target in the dark is not a trivial task. Fortunately for machine-gun owners, someone invented tracer bullets. Every so often, a tracer bullet is mixed in with the regular bullets. Tracer bullets contain a small amount of flare-like material that burns when fired, leaving a long, arcing trace in the sky.
So what do tracer bullets have to do with your software development work?
When you fire a tracer bullet, you can see exactly where it’s going. This lets you adjust your aim—in real time, under real conditions—to get the bullets right on target.