Revert "Remove unused import", silence warning
Revert "Remove unused import", silence warning

It *is* used on older versions of Rust. But do silence the warning on
more recent versions of Rust and explain what is going on.

This reverts commit cd967e4796037866fc69089965a454bfd3b696a6.

ruuda/claxon,ruuda/claxon,ruuda/claxon