feat(firebaseai): add metadata for bidi

packages/firebase_ai/firebase_ai/lib/src/live_api.dart

@@ -116,7 +116,11 @@ class LiveServerContent implements LiveServerMessage {
   /// [modelTurn] (optional): The content generated by the model.
   /// [turnComplete] (optional): Indicates if the turn is complete.
   /// [interrupted] (optional): Indicates if the generation was interrupted.
-  LiveServerContent({this.modelTurn, this.turnComplete, this.interrupted});
+  LiveServerContent(
+      {this.modelTurn,
+      this.turnComplete,
+      this.interrupted,
+      this.groundingMetadata});
 
   // TODO(cynthia): Add accessor for media content
   /// The content generated by the model.
@@ -129,6 +133,9 @@ class LiveServerContent implements LiveServerMessage {
   /// Whether generation was interrupted. If true, indicates that a
   /// client message has interrupted current model
   final bool? interrupted;
+
+  /// Metadata specifies sources used to ground generated content.
+  final GroundingMetadata? groundingMetadata;
 }
 
 /// A tool call in a live stream.
@@ -170,10 +177,13 @@ class LiveServerToolCallCancellation implements LiveServerMessage {
 /// ongoing generation.
 class LiveServerResponse {
   // ignore: public_member_api_docs
-  LiveServerResponse({required this.message});
+  LiveServerResponse({required this.message, this.usageMetadata});
 
   /// The server message generated by the live model.
   final LiveServerMessage message;
+
+  /// Usage metadata about the response(s).
+  final UsageMetadata? usageMetadata;
 }
 
 /// Represents realtime input from the client in a live stream.
@@ -286,7 +296,11 @@ class LiveClientToolResponse {
 /// - A [LiveServerResponse] object representing the parsed message.
 LiveServerResponse parseServerResponse(Object jsonObject) {
   LiveServerMessage message = _parseServerMessage(jsonObject);
-  return LiveServerResponse(message: message);
+  UsageMetadata? usageMetadata;
+  if (jsonObject case {'usageMetadata': final Object usageMetadataJson}) {
+    usageMetadata = parseUsageMetadata(usageMetadataJson);
+  }
+  return LiveServerResponse(message: message, usageMetadata: usageMetadata);
 }
 
 LiveServerMessage _parseServerMessage(Object jsonObject) {
@@ -295,7 +309,6 @@ LiveServerMessage _parseServerMessage(Object jsonObject) {
   }
 
   Map<String, dynamic> json = jsonObject as Map<String, dynamic>;
-
   if (json.containsKey('serverContent')) {
     final serverContentJson = json['serverContent'] as Map<String, dynamic>;
     Content? modelTurn;
@@ -306,7 +319,16 @@ LiveServerMessage _parseServerMessage(Object jsonObject) {
     if (serverContentJson.containsKey('turnComplete')) {
       turnComplete = serverContentJson['turnComplete'] as bool;
     }
-    return LiveServerContent(modelTurn: modelTurn, turnComplete: turnComplete);
+    GroundingMetadata? groundingMetadata;
+    if (serverContentJson.containsKey('groundingMetadata')) {
+      final groundingMetadataJson =
+          serverContentJson['groundingMetadata'] as Map<String, dynamic>;
+      groundingMetadata = parseGroundingMetadata(groundingMetadataJson);
+    }
+    return LiveServerContent(
+        modelTurn: modelTurn,
+        turnComplete: turnComplete,
+        groundingMetadata: groundingMetadata);
   } else if (json.containsKey('toolCall')) {
     final toolContentJson = json['toolCall'] as Map<String, dynamic>;
     List<FunctionCall> functionCalls = [];