docs: stop presenting the in-memory client as the way to connect (#3443)

docs_src/apps/tutorial001_client.py

@@ -0,0 +1,20 @@
+import anyio
+
+from mcp import Client
+from mcp.client import advertise
+from mcp.server.apps import APP_MIME_TYPE, EXTENSION_ID
+from mcp.types import TextContent
+
+APPS_SUPPORT = advertise(EXTENSION_ID, {"mimeTypes": [APP_MIME_TYPE]})
+
+
+async def main() -> None:
+    async with Client("http://localhost:8000/mcp", extensions=[APPS_SUPPORT]) as client:
+        result = await client.call_tool("get_time", {})
+        for block in result.content:
+            if isinstance(block, TextContent):
+                print(block.text)
+
+
+if __name__ == "__main__":
+    anyio.run(main)