fix: Add preview warnings for webhooks API access.

PiperOrigin-RevId: 899310186

Author: wanlin31

google/genai/client.py

@@ -49,6 +49,7 @@
 from ._interactions.resources import AsyncInteractionsResource as AsyncNextGenInteractionsResource, InteractionsResource as NextGenInteractionsResource
 from ._interactions.resources import WebhooksResource, AsyncWebhooksResource
 _interactions_experimental_warned = False
+_webhooks_preview_warned = False
 
 class AsyncGeminiNextGenAPIClientAdapter(_interactions.AsyncGeminiNextGenAPIClientAdapter):
   """Adapter for the Gemini NextGen API Client."""
@@ -202,6 +203,14 @@ def interactions(self) -> AsyncNextGenInteractionsResource:
 
   @property
   def webhooks(self) -> AsyncWebhooksResource:
+    global _webhooks_preview_warned
+    if not _webhooks_preview_warned:
+      _webhooks_preview_warned = True
+      warnings.warn(
+          'Webhooks usage is preview and may change in future versions.',
+          category=UserWarning,
+          stacklevel=1,
+      )
     return self._nextgen_client.webhooks
 
   @property
@@ -553,6 +562,14 @@ def interactions(self) -> NextGenInteractionsResource:
 
   @property
   def webhooks(self) -> WebhooksResource:
+    global _webhooks_preview_warned
+    if not _webhooks_preview_warned:
+      _webhooks_preview_warned = True
+      warnings.warn(
+          'Webhooks usage is preview and may change in future versions.',
+          category=UserWarning,
+          stacklevel=1,
+      )
     return self._nextgen_client.webhooks
 
   @property