Add example for progressive call results

Author: muzzammilshahid

examples/rpc_progressive_call_results/callee.dart

@@ -0,0 +1,32 @@
+import "dart:io";
+import "package:xconn/xconn.dart";
+
+const procedureDownload = "io.xconn.progress.download";
+
+Future<void> main() async {
+  var client = Client();
+  var session = await client.connect("ws://localhost:8080/ws", "realm1");
+
+  // Define function to handle received Invocation for "io.xconn.progress.download"
+  Result downloadHandler(Invocation inv) {
+    const int fileSize = 100; // Simulate a file size of 100 units
+
+    for (int i = 0; i <= fileSize; i += 10) {
+      final int progress = i * 100 ~/ fileSize; // Calculate progress percentage
+      inv.sendProgress([progress], null); // Send progress
+      sleep(const Duration(milliseconds: 500));
+    }
+
+    return Result(args: ["Download complete!"]);
+  }
+
+  // Register procedure "io.xconn.progress.download"
+  var registration = await session.register(procedureDownload, downloadHandler);
+  print("Registered procedure $procedureDownload successfully");
+
+  // Define a signal handler to catch the interrupt signal (Ctrl+C)
+  ProcessSignal.sigint.watch().listen((signal) async {
+    await session.unregister(registration);
+    await session.close();
+  });
+}

examples/rpc_progressive_call_results/caller.dart

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+import "dart:io";
+
+import "package:xconn/xconn.dart";
+
+const procedureDownload = "io.xconn.progress.download";
+
+Future<void> main() async {
+  var client = Client();
+  var session = await client.connect("ws://localhost:8080/ws", "realm1");
+
+  // Call procedure "io.xconn.progress.download"
+  var result = await session.callProgress(
+    procedureDownload,
+    (Result result) {
+      var progress = result.args[0]; // Current progress
+      print("Download progress: $progress%");
+    },
+  );
+
+  print(result.args[0]);
+
+  await session.close();
+  exit(0);
+}