let net_connection_domain_nth (d: domain) (n: int) (b: b)
: (req_uri * dst) option =
let test (d', _, _) = (d' = d) in
let connections' = List.filter test b.browser_connections in
begin if List.length connections' <= n then
None
else
let (_, uri, dst) = List.nth connections' n in
Some((uri, dst))
end