Illustrate network example

README.md

@@ -392,15 +392,16 @@ Here is a client that connects to address `addr` using network `net` and reads a
 
 ```ocaml
 let run_client ~net ~addr =
+  Switch.run ~name:"client" @@ fun sw ->
   traceln "Client: connecting to server";
-  Switch.run @@ fun sw ->
   let flow = Eio.Net.connect ~sw net addr in
   let b = Buffer.create 100 in
   Eio.Flow.copy flow (Eio.Flow.buffer_sink b);
   traceln "Client: received %S" (Buffer.contents b)
 ```
 
 Note: the `flow` is attached to `sw` and will be closed automatically when it finishes.
+We also named the switch here; this will appear in the trace output (see below).
 
 This can also be tested on its own using a mock network:
 
@@ -439,7 +440,7 @@ We can now run the client and server together using the real network (in a singl
 
 ```ocaml
 let main ~net ~addr =
-  Switch.run @@ fun sw ->
+  Switch.run ~name:"main" @@ fun sw ->
   let server = Eio.Net.listen net ~sw ~reuse_addr:true ~backlog:5 addr in
   Fiber.fork_daemon ~sw (fun () -> run_server server);
   run_client ~net ~addr
@@ -460,6 +461,10 @@ the test would never finish.
 - : unit = ()
 ```
 
+<p align='center'>
+  <img src="./doc/traces/net-posix.svg"/>
+</p>
+
 See [examples/net](./examples/net/) for a more complete example.
 
 ## Design Note: Capabilities

doc/traces/Makefile

@@ -1,4 +1,4 @@
-all: both-posix.svg cancel-posix.svg switch-mock.svg
+all: both-posix.svg cancel-posix.svg switch-mock.svg net-posix.svg
 
 %.svg: %.fxt
 	eio-trace render -f "$<" "$@"