plus

Concatenates this string with the string representation of the other object.

Here's an example of calling this function from Kotlin code:

val text: NotBlankString = "hello".toNotBlankString()
    .getOrThrow()
val message: NotBlankString = text + " world"
println(message) // hello world

The NotBlankString type being an inline value class, this function is not available yet for Java users.