# I need an hrule, but not when at the top of the page

I have a multi-page document that has many small sections split with \hrule lines. Occasionally a section will end immediately before a page break, and so the next section will begin right at the top of the next page. The \hrule above the new section on the new empty page then ends up looking silly.

Is it possible to define a macro like \hruleButOnlyIfNotAtTopOfPage?

Note that I'm using Plain TeX.

\vsize=4cm

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\r
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\r

\bye