import org.slf4j.Logger
import org.slf4j.LoggerFactory

inline fun <reified R : Any> R.logger(): Lazy<Logger> = lazy {
    if (R::class.isCompanion) LoggerFactory.getLogger(R::class.java.enclosingClass)
    else LoggerFactory.getLogger(R::class.java)
}

class Test {

    val logger by logger()

    companion object {
        val myLogger by logger()
    }

}

What’s the way to go declaring logger this days? by delegate, extension function, basic, using a library?

There are many libraries for kotlin logging. Quite a popular one is https://github.com/oshai/kotlin-logging