For logging in Android. Use through either companion object inheritance or delegating the implementation of the interface for other cases.

Tagger.kt

interface Tag {
    val tag: String

    val log: Tagger.TaggedLogger
}

open class Tagger(override val tag: String) : Tag {

    interface TaggedLogger {
        fun e(message: String)
        fun w(message: String)
        fun i(message: String)
        fun d(message: String)
        fun v(message: String)
    }

    override val log = object : TaggedLogger {
        override fun e(message: String) {
            Log.e(tag, message)
        }

        override fun w(message: String) {
            Log.w(tag, message)
        }

        override fun i(message: String) {
            Log.i(tag, message)
        }

        override fun d(message: String) {
            Log.d(tag, message)
        }

        override fun v(message: String) {
            Log.v(tag, message)
        }
    }
}