The expressions for the data you want to log out can be expensive, so ideally you only want to compute them after you’ve checked if the logger was enabled for t

The expressions for the data you want to log out can be expensive, so ideally you only want to compute them after you’ve checked if the logger was enabled for the level you need. In most APIs this requires an explicit conditional check and the average developer will not think of it. This allows said check to be performed internally.