refactor: Extract out platform specific code like threading

PiperOrigin-RevId: 769655650

src/google/adk/platform/__init__.py

@@ -0,0 +1,13 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

src/google/adk/platform/thread.py

@@ -0,0 +1,31 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+import threading
+from typing import Callable
+
+internal_thread = None
+try:
+  from .internal import thread as internal_thread
+except ImportError:
+  internal_thread = None
+
+
+def create_thread(target: Callable[..., None], *args, **kwargs):
+  """Creates a thread."""
+  if internal_thread:
+    return internal_thread.create_thread(target, *args, **kwargs)
+  return threading.Thread(target=target, args=args, kwargs=kwargs)

src/google/adk/runners.py

@@ -38,6 +38,7 @@ from .code_executors.built_in_code_executor import BuiltInCodeExecutor
 from .events.event import Event
 from .memory.base_memory_service import BaseMemoryService
 from .memory.in_memory_memory_service import InMemoryMemoryService
+from .platform.thread import create_thread
 from .sessions.base_session_service import BaseSessionService
 from .sessions.in_memory_session_service import InMemorySessionService
 from .sessions.session import Session
@@ -139,7 +140,7 @@ class Runner:
       finally:
         event_queue.put(None)
 
-    thread = threading.Thread(target=_asyncio_thread_main)
+    thread = create_thread(target=_asyncio_thread_main)
     thread.start()
 
     # consumes and re-yield the events from background thread.