Fix panic when dropping future for http::Client::send

tests/http_timeout.rs

@@ -0,0 +1,23 @@
+use wstd::future::FutureExt;
+use wstd::http::{Client, Method, Request};
+use wstd::time::Duration;
+
+#[wstd::test]
+async fn http_timeout() -> Result<(), Box<dyn std::error::Error>> {
+    // This get request will connect to the server, which will then wait 1 second before
+    // returning a response.
+    let request = Request::new(Method::GET, "https://postman-echo.com/delay/1".parse()?);
+    let result = Client::new()
+        .send(request)
+        .timeout(Duration::from_millis(500))
+        .await;
+
+    assert!(result.is_err(), "response should be an error");
+    let error = result.unwrap_err();
+    assert!(
+        matches!(error.kind(), std::io::ErrorKind::TimedOut),
+        "expected TimedOut error, got: {error:?>}"
+    );
+
+    Ok(())
+}