exmaples: add --verify option in the query example

examples/query.rs

@@ -27,6 +27,12 @@ fn main() {
     };
     service_type.push_str(".local.");
 
+    // Showcase `verify` functionality for IPv4 addresses
+    let should_verify = match std::env::args().nth(2) {
+        Some(arg) if arg == "--verify" => true,
+        _ => false,
+    };
+
     // Create a daemon
     let mdns = ServiceDaemon::new().expect("Failed to create daemon");
 
@@ -44,12 +50,35 @@ fn main() {
                     info.host,
                     info.port,
                 );
+                let mut found_ipv4 = false;
                 for addr in info.addresses.iter() {
                     println!(" Address: {addr}");
+                    if addr.is_ipv4() {
+                        found_ipv4 = true;
+                    }
                 }
                 for prop in info.txt_properties.iter() {
                     println!(" Property: {}", prop);
                 }
+
+                if should_verify && found_ipv4 {
+                    println!("Will verify after 3 seconds...");
+                    std::thread::sleep(std::time::Duration::from_secs(3));
+
+                    let instance_fullname = info.fullname;
+                    let timeout = std::time::Duration::from_secs(2);
+                    if let Err(e) = mdns.verify(instance_fullname, timeout) {
+                        println!("Verify failed: {}", e);
+                    } else {
+                        println!("Verify started");
+                    }
+                }
+            }
+            ServiceEvent::ServiceRemoved(service_type, fullname) => {
+                println!(
+                    "At {:?}: ** service removed **: {service_type}: {fullname}",
+                    now.elapsed(),
+                );
             }
             other_event => {
                 println!("At {:?}: {:?}", now.elapsed(), &other_event);
@@ -59,10 +88,13 @@ fn main() {
 }
 
 fn print_usage() {
-    println!("Usage: cargo run --example query <service_type_without_domain_postfix>");
+    println!("Usage: cargo run --example query <service_type_without_domain_postfix> [--verify]");
     println!("Example: ");
     println!("cargo run --example query _my-service._udp");
     println!();
+    println!("Options:");
+    println!("--verify: make the client attempt to verify IPv4 addresses of resolved services.");
+    println!();
     println!("You can also do a meta-query per RFC 6763 to find which services are available:");
     println!("cargo run --example query _services._dns-sd._udp");
 }