Creates a new #GString with @len bytes of the @init buffer. Because a length is provided, @init need not be nul-terminated, and can contain embedded nul bytes.
fun sizedNew(dflSize: <Error class: unknown class>): String
Creates a new #GString, with enough space for @dfl_size bytes. This is useful if you are going to add a lot of text to the string and don't want it to be reallocated too often.