feat(llc,core,ui): send used package in the headers

packages/stream_chat/lib/version.dart

@@ -1,6 +1,40 @@
 import 'package:stream_chat/src/client/client.dart';
+import 'package:stream_chat/src/core/platform_detector/platform_detector.dart';
 
 /// Current package version
 /// Used in [StreamChatClient] to build the `x-stream-client` header
 // ignore: constant_identifier_names
 const PACKAGE_VERSION = '3.2.0';
+
+/// Default user agent used for the 'x-stream-client' header
+final defaultUserAgent = 'stream-chat-dart-client-'
+    '${CurrentPlatform.name}-'
+    '${PACKAGE_VERSION.split('+')[0]}';
+
+/// Current used package
+/// This is used to set the `x-stream-client` header using info about
+/// the package in use
+/// For example: llc/core/ui
+Package usedPackage = Package.llc;
+
+/// Possible packages
+enum Package {
+  /// The Low Level Client
+  llc,
+
+  /// The Core package
+  core,
+
+  /// The UI package
+  ui,
+}
+
+///
+extension XPackage on Package {
+  ///
+  String get name => {
+        Package.llc: 'llc',
+        Package.core: 'core',
+        Package.ui: 'ui',
+      }[this]!;
+}