# IMPORTANT MODULES FOR THIS CODE...
use CGI qw(-utf8); 
use File::Spec::Functions qw( catfile );

sub send_file {
    my ($cgi, $dir, $file) = @_;

    # $dir = '/var/www/download/';
    # $file = 'MyLaTeXDocument.pdf';

    my $path = catfile($dir, $file);
    	
    open my $fh, '<:raw', $path or die "Cannot open '$path': $!\n";

    $cgi->charset(''); #REMOVES PRIOR UTF-8 SETTING, AS THIS IS BINARY FILE
    print $cgi->header(
        -type => 'application/octet-stream',
        -attachment => $file,
    );

    binmode STDOUT, ':raw';
    print while <$fh>;    
    close $fh or die "Cannot close '$path': $!";

    return;
}

##</code><code>##

Connection
	Keep-Alive
Content-Disposition
	attachment; filename="MyLaTeXDocument.pdf"
Content-Type
	application/octet-stream
Date
	Fri, 22 Sep 2023 11:13:27 GMT
Keep-Alive
	timeout=5, max=100
Server
	Apache/2.4.52 (Ubuntu)
Transfer-Encoding
	chunked

##</code><code>##

JVBERi0xLjUKJeTw7fg... [truncated...too lazy to type more]