Fix websocket server functions and add an example (#4107)

* Fix websocket server function

* Add websocket test

* add a websocket example

* fix clippy

examples/fullstack-websockets/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "fullstack-websocket-example"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+dioxus = { workspace = true, features = ["fullstack"] }
+futures.workspace = true
+tokio = { workspace = true, features = ["full"], optional = true }
+
+[features]
+server = ["dioxus/server", "dep:tokio"]
+web = ["dioxus/web"]