Cases:
  http://timeout.qoph.org/hang/file.png       connection hangs: no headers, no data
  http://timeout.qoph.org/stall/file.png      headers and first 64 KB, then the transfer stops
  http://timeout.qoph.org/slow/file.png       file is sent evenly over 2 minutes
  http://timeout.qoph.org/truncate/file.png   connection is dropped after 64 KB
  http://timeout.qoph.org/ok/file.png         file is sent immediately