client: set random id correctly

* set_random_id won't work in WASM

src/client.rs

@@ -44,7 +44,9 @@ impl Client {
     // it first, and we also want to be able to do caching and overriding
     fn build_query(questions: Vec<Question<ParsedDname>>) -> Result<Message, String> {
         let mut builder = MessageBuilder::new_udp();
-        builder.header_mut().set_random_id();
+        builder
+            .header_mut()
+            .set_id((unsafe { Math::random() } * u16::MAX as f64) as u16);
         for q in questions {
             builder
                 .push(q)