+=item C<send_file $file_name_or_content, [%params]>
+
+Sends the file C<$file_name_or_content> to the browser including
+appropriate HTTP headers for a download. If C<$file_name_or_content>
+is a scalar then it is interpreted as a file name which is opened and
+whose content is sent. Otherwise (C<$file_name_or_content> being a
+reference) the referenced scalar's data itself is sent.