diff --git a/examples/fnv1_udp/client.ml b/examples/fnv1_udp/client.ml
new file mode 100644
index 0000000..83a01b0
--- /dev/null
+++ b/examples/fnv1_udp/client.ml
@@ -0,0 +1,104 @@
+module Net = Nanoev_picos.Net
+module Trace = Trace_core
+
+let ( let@ ) = ( @@ )
+let port = ref 9427
+let j = ref (Domain.recommended_domain_count ())
+let n_iters = ref 200
+let n_tasks = ref 100
+let reset_line = "\x1b[2K\r"
+
+(** Message we send *)
+let txt = String.init 100 (fun i -> Char.chr (Char.code 'a' + (i mod 26)))
+
+let main () : unit =
+  let n_tasks_done = Atomic.make 0 in
+  let n_sent = Atomic.make 0 in
+  let n_recv = Atomic.make 0 in
+  ignore
+    (Thread.create
+       (fun () ->
+         while true do
+           Printf.printf "%stasks done: %d sent: %d recv: %d%!" reset_line
+             (Atomic.get n_tasks_done) (Atomic.get n_sent) (Atomic.get n_recv);
+
+           Trace.counter_int "task-done" (Atomic.get n_tasks_done);
+           Trace.counter_int "sent" (Atomic.get n_sent);
+           Trace.counter_int "recv" (Atomic.get n_recv);
+
+           Thread.delay 0.2
+         done)
+       ()
+      : Thread.t);
+
+  (let@ pool = Moonpool.Ws_pool.with_ ~num_threads:!j () in
+
+   let remoteaddr = Unix.ADDR_INET (Unix.inet_addr_loopback, !port) in
+
+   let task () =
+     let[@alert "-deprecated"] _sp =
+       Trace.enter_manual_toplevel_span ~__FILE__ ~__LINE__ "task.run"
+     in
+
+     let sock = Unix.socket Unix.PF_INET Unix.SOCK_DGRAM 0 in
+     Unix.set_nonblock sock;
+
+     let buf_read = Bytes.create 9 in
+     for _i = 1 to !n_iters do
+       let ack = Atomic.make false in
+
+       (* response might get lost, so we send a message until
+          we get a response *)
+       let fut =
+         Moonpool.spawn ~on:pool @@ fun () ->
+         while not (Atomic.get ack) do
+           let _n =
+             Net.sendto sock ~addr:remoteaddr ~flags:[]
+               (Bytes.unsafe_of_string txt)
+               0 (String.length txt)
+           in
+           Atomic.incr n_sent;
+           assert (_n = 100);
+           (* retry later *)
+           Nanoev_picos.sleep 0.001
+         done
+       in
+
+       Picos.Fiber.(yield ());
+
+       (* receive a response *)
+       let _n, _remote = Net.recvfrom sock buf_read 0 9 ~flags:[] in
+       assert (_n = 8);
+       Atomic.incr n_recv;
+       Atomic.set ack true;
+
+       (* cleanup *)
+       Moonpool.await fut
+     done;
+
+     Unix.close sock;
+     Atomic.incr n_tasks_done;
+     Trace.exit_manual_span _sp
+   in
+
+   let tasks = Dynarray.create () in
+   for _i = 1 to !n_tasks do
+     Dynarray.add_last tasks (Moonpool.spawn ~on:pool task)
+   done;
+   Dynarray.iter Moonpool.Fut.wait_block_exn tasks);
+  Printf.printf "%sall done\n%!" reset_line
+
+let () =
+  let@ () = Trace_tef.with_setup () in
+  Arg.parse
+    (Arg.align
+       [
+         "-p", Arg.Set_int port, " set port";
+         "-j", Arg.Set_int j, " thread pool size";
+         "--n-tasks", Arg.Set_int n_tasks, " number of tasks";
+         "--n-iters", Arg.Set_int n_iters, " number of iterations per task";
+       ])
+    ignore "";
+  Nanoev_picos.Background_thread.setup @@ Nanoev_posix.create ();
+  let@ _run = Moonpool_fib.main in
+  main ()
diff --git a/examples/fnv1_udp/dune b/examples/fnv1_udp/dune
new file mode 100644
index 0000000..7f7f7a5
--- /dev/null
+++ b/examples/fnv1_udp/dune
@@ -0,0 +1,4 @@
+(executables
+ (names server client)
+ (libraries moonpool moonpool.fib nanoev nanoev-picos nanoev-posix trace.core
+   trace-tef))
diff --git a/examples/fnv1_udp/server.ml b/examples/fnv1_udp/server.ml
new file mode 100644
index 0000000..b51d267
--- /dev/null
+++ b/examples/fnv1_udp/server.ml
@@ -0,0 +1,75 @@
+module Net = Nanoev_picos.Net
+module Trace = Trace_core
+
+let ( let@ ) = ( @@ )
+let port = ref 9427
+let j = ref (Domain.recommended_domain_count ())
+
+(** FNV hashing
+    https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
+*)
+module FNV = struct
+  let fnv_offset_basis = 0xcbf29ce484222325L
+  let fnv_prime = 0x100000001b3L
+
+  let bytes ?len (x : bytes) : int64 =
+    let h = ref fnv_offset_basis in
+    let len = Option.value ~default:(Bytes.length x) len in
+    for i = 0 to len - 1 do
+      (h := Int64.(mul !h fnv_prime));
+      let byte = Char.code (Bytes.unsafe_get x i) in
+      h := Int64.(logxor !h (of_int byte))
+    done;
+    Int64.(logand !h max_int)
+
+  let string (x : string) = bytes (Bytes.unsafe_of_string x)
+end
+
+let n_requests = Atomic.make 0
+let n_replies = Atomic.make 0
+
+let main () : unit =
+  let sock = Unix.socket Unix.PF_INET Unix.SOCK_DGRAM 0 in
+  Unix.set_nonblock sock;
+  Unix.bind sock (Unix.ADDR_INET (Unix.inet_addr_any, !port));
+
+  let@ pool = Moonpool.Ws_pool.with_ ~num_threads:!j () in
+
+  if Trace.enabled () then
+    ignore
+      (Thread.create
+         (fun () ->
+           while true do
+             Trace.counter_int "n-requests" (Atomic.get n_requests);
+             Trace.counter_int "n-replies" (Atomic.get n_replies);
+
+             Thread.delay 0.2
+           done)
+         ()
+        : Thread.t);
+
+  let buf = Bytes.create 1024 in
+  while true do
+    let n, remoteaddr = Net.recvfrom sock buf 0 (Bytes.length buf) ~flags:[] in
+    Atomic.incr n_requests;
+    let buf2 = Bytes.sub buf 0 n in
+    Moonpool.run_async pool (fun () ->
+        let h = FNV.bytes buf2 in
+        let buf_ref = Bytes.create 8 in
+        Bytes.set_int64_le buf_ref 0 h;
+        ignore (Net.sendto sock ~addr:remoteaddr buf_ref 0 8 ~flags:[] : int));
+    Atomic.incr n_replies
+  done
+
+let () =
+  let@ () = Trace_tef.with_setup () in
+  Arg.parse
+    (Arg.align
+       [
+         "-p", Arg.Set_int port, " set port";
+         "-j", Arg.Set_int j, " thread pool size";
+       ])
+    ignore "";
+  Nanoev_picos.Background_thread.setup @@ Nanoev_posix.create ();
+  let@ _run = Moonpool_fib.main in
+  main ()