Add example file

example/main.dart

@@ -0,0 +1,56 @@
+import 'package:flutter/material.dart';
+import 'package:multiple_stream_builder/multiple_stream_builder.dart';
+
+void main() {
+  runApp(const ExampleApp());
+}
+
+class ExampleApp extends StatelessWidget {
+  const ExampleApp({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Multiple Stream Builder Example',
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text('Multiple Stream Builder Example'),
+        ),
+        body: const ExampleScreen(),
+      ),
+    );
+  }
+}
+
+class ExampleScreen extends StatefulWidget {
+  const ExampleScreen({Key? key}) : super(key: key);
+
+  @override
+  State<ExampleScreen> createState() => _ExampleScreenState();
+}
+
+class _ExampleScreenState extends State<ExampleScreen> {
+  var stream1 = Stream<int>.periodic(const Duration(seconds: 1), (x) => x);
+  var stream2 = Stream<int>.periodic(const Duration(seconds: 2), (x) => x);
+  var stream3 = Stream<int>.periodic(const Duration(seconds: 3), (x) => x);
+
+  @override
+  Widget build(BuildContext context) {
+    return StreamBuilder3<int, int, int>(
+      streams: StreamTuple3(stream1, stream2, stream3),
+      initialData: InitialDataTuple3(0, 0, 0),
+      builder: (context, snapshots) {
+        return Center(
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              Text('stream1: ${snapshots.snapshot1.data}'),
+              Text('stream2: ${snapshots.snapshot2.data}'),
+              Text('stream3: ${snapshots.snapshot3.data}'),
+            ],
+          ),
+        );
+      },
+    );
+  }
+}