Add documentation

docs/websockets.md

@@ -95,6 +95,55 @@ effect type      class name
 ================ ==========================================
 ```
 
+## WebSockets as Ox Source and Sink
+
+[Ox](https://ox.softwaremill.com) is a Scala 3 toolkit that allows you to handle concurrency and resiliency in direct-style, leveraging Java 21 virtual threads.
+If you're using Ox with `sttp`, you can use the `DefaultSyncBackend` from `sttp-core` for HTTP communication. An additional `ox` module allows handling WebSockets 
+as Ox `Source` and `Sink`:
+
+```
+// sbt dependency
+"com.softwaremill.sttp.client4" %% "ox" % "@VERSION@",
+```
+
+```scala 
+import ox.*
+import ox.channels.{Sink, Source}
+import sttp.client4.*
+import sttp.client4.impl.ox.ws.* // import to access asSourceAnkSink
+import sttp.client4.ws.SyncWebSocket
+import sttp.client4.ws.sync.*
+import sttp.ws.WebSocketFrame
+
+def useWebSocket(ws: SyncWebSocket): Unit =
+    supervised {
+      val (wsSource, wsSink) = asSourceAndSink(ws) // (Source[WebSocketFrame], Sink[WebSocketFrame])
+      // ...
+    }
+
+val backend = DefaultSyncBackend()
+basicRequest
+  .get(uri"wss://ws.postman-echo.com/raw")
+  .response(asWebSocket(useWebSocket))
+  .send(backend)
+```
+
+See the [full example here](https://github.com/softwaremill/sttp/blob/master/examples/src/main/scala/sttp/client4/examples3/WebSocketOx.scala).
+
+Make sure that the `Source` is contiunually read. This will guarantee that server-side Close signal is received and handled.
+If you don't want to process frames from the server, you can at least handle it with a `fork { source.drain() }`.
+
+You don't need to manually call `ws.close()` when using this approach, this will be
+handled automatically underneath, according to following rules:
+ - If the request `Sink` fails with an error, the `Source` is automatically completed, sending a `Close` frame to
+   the server if needed.
+ - If the request `Sink` completes without an error, a `Close` frame is sent, and the response `Sink` keeps
+   receiving responses until the server closes communication.
+ - If the response `Source` is completed (either due to completion or an error), the request Sink is completed,
+   right after sending all outstanding buffered frames.
+
+Read more about Ox, structured concurrency, Sources and Sinks on the [project website](https://ox.softwaremill.com).
+
 ## Compression
 
 For those who plan to use a lot of websocket traffic, you could consider websocket compression. See the information on
@@ -122,4 +171,4 @@ Web socket settings can be adjusted by providing a custom `AsyncHttpClientConfig
 Some available settings:
 
 * maximum web socket frame size. Default: 10240, can be changed using `.setWebSocketMaxFrameSize`.
-* compression. Default: false, can be changed using: `.setEnablewebSocketCompression`.
+* compression. Default: false, can be changed using: `.setEnablewebSocketCompression`.