eio(client): Add timeout example

cohttp-eio/examples/client_timeout.ml

@@ -0,0 +1,19 @@
+open Eio
+open Cohttp_eio
+
+let () =
+  Eio_main.run @@ fun env ->
+  Switch.run @@ fun sw ->
+  (* Increment/decrement this value to see success/failure. *)
+  let timeout_s = 0.01 in
+  Eio.Time.with_timeout env#clock timeout_s (fun () ->
+      let hostname, port = ("www.example.org", 80) in
+      let he = Unix.gethostbyname hostname in
+      let addr = `Tcp (Eio_unix.Ipaddr.of_unix he.h_addr_list.(0), port) in
+      let conn = Net.connect ~sw env#net addr in
+      let host = (hostname, Some port) in
+      let res = Client.get ~conn host "/" in
+      Client.read_fixed res |> Result.ok)
+  |> function
+  | Ok s -> print_string s
+  | Error `Timeout -> print_string "Connection timed out"

cohttp-eio/examples/dune

@@ -1,5 +1,5 @@
 (executables
- (names server1 client1 docker_client)
+ (names server1 client1 docker_client client_timeout)
  (libraries cohttp-eio eio_main eio.unix unix))
 
 (alias