昨天介紹了委任以及覆寫成員的特性
今天則要繼續深入介紹委任的性質

如下範例
當我們試著從p去讀取時，由於委任性質的緣故
來自Delegate的getValue()函式會被呼叫
並印出以下字串Example@33a17727, thank you for delegating 'p' to me!

class Example {
    var p: String by Delegate()
}

import kotlin.reflect.KProperty

class Delegate {
    operator fun getValue(thisRef: Any?, property: KProperty<*>): String {
        return "$thisRef, thank you for delegating '${property.name}' to me!"
    }

    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
        println("$value has been assigned to '${property.name}' in $thisRef.")
    }
}