找出单例委托里的 bug

import kotlin.properties.ReadWriteProperty
import kotlin.reflect.KProperty

object SharedText : ReadWriteProperty<Any?, String> {
    private var value = ""

    override fun getValue(thisRef: Any?, property: KProperty<*>): String = value

    override fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
        this.value = value.trim()
    }
}

class ContactForm {
    var name: String by SharedText
    var city: String by SharedText
}