$| = 1;  # Pufferung aus
my $content = '0123456789abcdef' x ( 64 * 1000 );  # Blödsinn erzeugen
print "Content-Type: application/octet-stream\n";  # Header 1
print "Content-length: " . length ($content) . "\n";  # Header 2
print "Content-Disposition: attachment; filename=\"testdatei.bin\"";  # Header 3
print "\n\n";

# Ausgabe verzögern, damit das Problem noch deutlicher wird:
my $pos = 0;
my $partlength = 20_480;
while ( my $part = substr( $content, $pos, $partlength ) ) {
  print $part;
  $pos+=$partlength;
  sleep 1;
}