var property.
Only initial value of a property is used for delegation, any later assignments do not affect it.
Example:
class Example(var text: CharSequence): CharSequence by text
A quick-fix replaces a property with immutable one:
class Example(val text: CharSequence): CharSequence by text
Alternative way, if you rely on mutability for some reason:
class Example(text: CharSequence): CharSequence by text {
var text = text
}