chore: add experimental messages for a2a related API

PiperOrigin-RevId: 793812544

src/google/adk/a2a/executor/a2a_agent_executor.py

@@ -50,23 +50,23 @@ from google.adk.runners import Runner
 from pydantic import BaseModel
 from typing_extensions import override
 
-from ...utils.feature_decorator import experimental
 from ..converters.event_converter import convert_event_to_a2a_events
 from ..converters.request_converter import convert_a2a_request_to_adk_run_args
 from ..converters.utils import _get_adk_metadata_key
+from ..experimental import a2a_experimental
 from .task_result_aggregator import TaskResultAggregator
 
 logger = logging.getLogger('google_adk.' + __name__)
 
 
-@experimental
+@a2a_experimental
 class A2aAgentExecutorConfig(BaseModel):
   """Configuration for the A2aAgentExecutor."""
 
   pass
 
 
-@experimental
+@a2a_experimental
 class A2aAgentExecutor(AgentExecutor):
   """An AgentExecutor that runs an ADK Agent against an A2A request and
   publishes updates to an event queue.

src/google/adk/a2a/executor/task_result_aggregator.py

@@ -19,10 +19,10 @@ from a2a.types import Message
 from a2a.types import TaskState
 from a2a.types import TaskStatusUpdateEvent
 
-from ...utils.feature_decorator import experimental
+from ..experimental import a2a_experimental
 
 
-@experimental
+@a2a_experimental
 class TaskResultAggregator:
   """Aggregates the task status updates and provides the final task state."""