HAPROXY: Delay but fullfil a request if it was made with an outdated (but supported) cipher

haproxy.conf

frontend http
  mode http
  bind :443 ssl crt /etc/haproxy/ssl

  acl outdated_cipher ssl_fc_cipher -i -m sub rc4

  # define a maximum waiting period
  tcp-request inspect-delay 10s

  # accept the connection immediately if the client doesn't use an outdated cipher
  tcp-request content accept unless outdated_cipher

  # accept all other requests only once the inspect-delay has passed
  tcp-request content accept if WAIT_END

  use-backend my-servers

backend my-servers
  server 127.0.09.1:8000
  server 127.0.09.1:8001
  # ...