adding flag to show connect device as group

discovery/examples/discovery_group.rs

@@ -0,0 +1,22 @@
+use futures::StreamExt;
+use librespot_core::SessionConfig;
+use librespot_discovery::DeviceType;
+use sha1::{Digest, Sha1};
+
+#[tokio::main(flavor = "current_thread")]
+async fn main() {
+    let name = "Librespot Group";
+    let device_id = hex::encode(Sha1::digest(name.as_bytes()));
+
+    let mut server =
+        librespot_discovery::Discovery::builder(device_id, SessionConfig::default().client_id)
+            .name(name)
+            .device_type(DeviceType::Speaker)
+            .is_group(true)
+            .launch()
+            .unwrap();
+
+    while let Some(x) = server.next().await {
+        println!("Received {:?}", x);
+    }
+}