add lwt test

test/lwt/dune

@@ -0,0 +1,7 @@
+
+
+(test
+  (name t1)
+  (package trace-lwt)
+  (libraries trace trace-tef trace-lwt lwt lwt.unix))
+

test/lwt/t1.ml

@@ -0,0 +1,77 @@
+open Lwt.Syntax
+
+let ( let@ ) = ( @@ )
+
+let inner_loop i =
+  let rec loop j =
+    if j >= 5 then
+      Lwt.return ()
+    else
+      let* () =
+        let@ _sp =
+          Trace_lwt.with_span_lwt ~__FILE__ ~__LINE__ "inner.loop.step"
+        in
+        Trace.messagef (fun k -> k "hello %d %d" i j);
+        Trace.message "world";
+
+        let* () =
+          if j = 2 then
+            let@ _sp =
+              Trace_lwt.with_span_lwt ~__FILE__ ~__LINE__ "sub-sleep"
+            in
+            Lwt_unix.sleep 0.010
+          else
+            Lwt.return ()
+        in
+
+        Lwt_unix.sleep 0.006
+      in
+
+      loop (j + 1)
+  in
+  let@ _sp =
+    Trace_lwt.with_span_lwt ~force_toplevel:true ~__FILE__ ~__LINE__
+      "inner.loop"
+  in
+  loop 0
+
+let outer_loop () =
+  let rec loop i =
+    if i = 50 then
+      Lwt.return ()
+    else
+      let* () =
+        let@ _sp =
+          Trace_lwt.with_span_lwt ~__FILE__ ~__LINE__ "outer.loop.step"
+        in
+
+        let fut_sleep =
+          let@ _sp =
+            Trace_lwt.with_span_lwt ~__FILE__ ~__LINE__ "outer.sleep"
+          in
+          Lwt_unix.sleep 0.09
+        in
+
+        let* () = inner_loop i and* () = inner_loop i in
+        let* () = fut_sleep in
+        Lwt.return ()
+      in
+      loop (i + 1)
+  in
+
+  let@ _sp =
+    Trace_lwt.with_span_lwt ~force_toplevel:true ~__FILE__ ~__LINE__
+      "outer.loop"
+  in
+  loop 0
+
+let run () : unit Lwt.t =
+  Trace.set_process_name "main";
+  Trace.set_thread_name "t1";
+
+  let* () = outer_loop () and* () = outer_loop () in
+  Lwt.return ()
+
+let () =
+  Trace_tef.Internal_.mock_all_ ();
+  Trace_tef.with_setup ~out:`Stdout () @@ fun () -> Lwt_main.run (run ())