remove NATS integration

examples/smartsend_example.rs

@@ -26,7 +26,7 @@ async fn main() {
     ];
 
     let options = SmartsendOptions {
-        broker_url: "nats://localhost:4222".to_string(),
+        broker_url: "localhost:4222".to_string(),
         fileserver_url: "http://localhost:8080".to_string(),
         msg_purpose: "chat".to_string(),
         sender_name: "rust-example".to_string(),
@@ -60,7 +60,7 @@ async fn main() {
             }
 
             println!();
-            println!("=== JSON String for NATS Publishing ===");
+            println!("=== JSON String for Transport Publishing ===");
             println!("{}", json_str);
         }
         Err(e) => {