calls. Say you need to log some expensive value:

	slog.Debug("frobbing", "value", computeExpensiveValue(arg))

Even if this line is disabled, computeExpensiveValue will be called.
To avoid that, define a type implementing LogValuer:

	type expensive struct { arg int }

	func (e expensive) LogValue() slog.Value {
	    return slog.AnyValue(computeExpensiveValue(e.arg))
	}

Then use a value of that type in log calls: