Add change connection data

lib/src/client.dart

@@ -50,6 +50,10 @@ abstract class Client {
   ///
   void setToken(String token);
 
+  /// Set allows updating connection data.
+  ///
+  void setData(List<int> data);
+
   /// Ready resolves when client successfully connected.
   /// Throws exceptions if called not in connecting or connected state.
   Future<void> ready();
@@ -197,6 +201,11 @@ class ClientImpl implements Client {
     _token = token;
   }
 
+  @override
+  void setData(List<int> data) {
+    _data = data;
+  }
+
   @override
   Future<void> disconnect() async {
     _reconnectAttempts = 0;
@@ -463,8 +472,9 @@ class ClientImpl implements Client {
     if (_token != '') {
       request.token = _token;
     }
-    if (_data != null) {
-      request.data = _data!;
+    final data = await _config.getData?.call() ?? _data;
+    if (data != null) {
+      request.data = data;
     }
     request.name = _config.name;
     request.version = _config.version;

lib/src/client_config.dart

@@ -13,6 +13,7 @@ class ClientConfig {
     this.token = '',
     this.getToken,
     this.data,
+    this.getData,
     this.headers = const <String, dynamic>{},
     this.tlsSkipVerify = false,
     this.timeout = const Duration(seconds: 10),
@@ -32,6 +33,9 @@ class ClientConfig {
   /// The data send for the first request
   List<int>? data;
 
+  /// Callback to get/refresh connection data
+  final ConnectDataCallback? getData;
+
   /// The connection timeout
   final Duration timeout;
 
@@ -53,3 +57,5 @@ class ClientConfig {
 }
 
 typedef ConnectionTokenCallback = Future<String> Function(ConnectionTokenEvent);
+
+typedef ConnectDataCallback = Future<List<int>>? Function();