+Server accepted connection from client
+Server received: "Hello from client"
+client received: "Bye"

$ cat test_run_server.ml
open Eio

let addr = `Tcp (Eio.Net.Ipaddr.V4.loopback, 8081)

let read_all flow =
  let b = Buffer.create 100 in
  Eio.Flow.copy flow (Eio.Flow.buffer_sink b);
  Buffer.contents b

let eio_run_server ~clients env sw =
  let run_client id () =
    traceln "client: Connecting to server ...%d" id;
    let flow = Eio.Net.connect ~sw env#net addr in
    Eio.Flow.copy_string "Hello from client" flow;
    Eio.Flow.shutdown flow `Send;
    let msg = read_all flow in
    traceln "client received: %S" msg;
  in
  let connection_handler clock flow _addr =
    traceln "Server accepted connection from client";
    Fun.protect (fun () ->
      let msg = read_all flow in
      traceln "Server received: %S" msg;
      Eio.Time.sleep clock 0.01
    ) ~finally:(fun () -> Eio.Flow.copy_string "Bye" flow)
  in
  let server_sock = Eio.Net.listen ~reuse_addr:true ~backlog:128 ~sw env#net addr in
  let connection_handler = connection_handler env#clock in
  let clients = List.init clients (fun id -> run_client (id+1)) in
  let server () =
    traceln "starting server ..."; 
    Eio.Net.accept_fork ~sw server_sock ~on_error:raise connection_handler 
  in
  Fiber.all (server :: clients)

let () =
  let clients = ref 60 in
  Arg.parse
    [ ("-clients", Arg.Set_int clients, " total clients to spawn")]
    ignore "test Eio.Net.fork_accept()";

  Printexc.record_backtrace true ;
  Eio_main.run @@ fun env ->
  Switch.run @@ fun sw ->
  eio_run_server ~clients:!clients env sw

$ cat dune
(executable (name test_run_server) (libraries eio eio_main))