\hrulefill vertically aligns the line at the bottom of the text.
There is also
\xrfill in the package
xhfill which raises the line, but it is raised too much for my esthetics.
What I'm looking for is a command working similarly to
\hrulefill, but such that the filler line is like a stretched em-dash, so the vertical alignment is the same as for an em-dash.
As a clarification: I don't want to have to guess the thickness nor the amount the line is raised over the baseline. I want a command which produces a stretched em-dashed, independently of the current font size etc.