vdi: new message loop

vdi/host/src/connection.rs

@@ -1 +1,11 @@
 use hbb_common::{message_proto::*, tokio, ResultType};
+pub use tokio::sync::{mpsc, Mutex};
+pub struct Connection {
+    pub tx: mpsc::UnboundedSender<Message>,
+}
+
+impl Connection {
+    pub async fn on_message(&mut self, message: Message) -> ResultType<bool> {
+        Ok(true)
+    }
+}