Fwd: Showing text on a specific line in the gutter

[Zdravetz Dukmedjiev <ataksiq gmail com>]

I don't see any way that the GtkSourceView reference page
provides in order to render DIFFERENT texts in different lines
in the gutter source gutter and I am not talking about the
source mark gutter but a custom gutter expansion
(as described: a custom gtksourcegutter renderer packed expands the gutter
in width)

by setting text to the renderer with the provided function,
the text is getting shown for each line as there is no iterator to be
specified.

How can I make it render only to a specific line?