chore: import upstream snapshot with attribution

contributing/samples/workflows/use_as_output/agent.py

@@ -0,0 +1,41 @@
+# Copyright 2026 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 google.adk import Agent
+from google.adk import Context
+from google.adk.workflow import node
+from google.adk.workflow import Workflow
+from google.adk.workflow._base_node import START
+
+summarizer = Agent(
+    name='summarizer',
+    instruction='Summarize the following text in one sentence.',
+)
+
+
+@node(rerun_on_resume=True)
+async def orchestrate(ctx: Context, node_input: str) -> str:
+  return await ctx.run_node(
+      summarizer, node_input=node_input, use_as_output=True
+  )
+
+
+def finalize(node_input: str) -> str:
+  return f'final: {node_input}'
+
+
+root_agent = Workflow(
+    name='root_agent',
+    edges=[(START, orchestrate, finalize)],
+)