Add Kotlin to the session rewind page

docs/sessions/session/rewind.md

@@ -1,7 +1,7 @@
 # Rewind sessions for agents
 
 <div class="language-support-tag">
-  <span class="lst-supported">Supported in ADK</span><span class="lst-python">Python v1.17.0</span>
+  <span class="lst-supported">Supported in ADK</span><span class="lst-python">Python v1.17.0</span><span class="lst-kotlin">Kotlin v0.3.0</span>
 </div>
 
 The ADK session Rewind feature allows you to revert a session to a previous
@@ -19,36 +19,44 @@ rewind a session by using the rewind method on a ***Runner*** instance,
 specifying the user, session, and invocation id, as shown in the following code
 snippet:
 
-```python
-# Create runner
-runner = InMemoryRunner(
-    agent=agent.root_agent,
-    app_name=APP_NAME,
-)
-
-# Create a session
-session = await runner.session_service.create_session(
-    app_name=APP_NAME, user_id=USER_ID
-)
-# call agent with wrapper function "call_agent_async()"
-await call_agent_async(
-    runner, USER_ID, session.id, "set state color to red"
-)
-# ... more agent calls ...
-events_list = await call_agent_async(
-    runner, USER_ID, session.id, "update state color to blue"
-)
-
-# get invocation id
-rewind_invocation_id=events_list[1].invocation_id
-
-# rewind invocations (state color: red)
-await runner.rewind_async(
-    user_id=USER_ID,
-    session_id=session.id,
-    rewind_before_invocation_id=rewind_invocation_id,
-)
-```
+=== "Python"
+
+    ```python
+    # Create runner
+    runner = InMemoryRunner(
+        agent=agent.root_agent,
+        app_name=APP_NAME,
+    )
+
+    # Create a session
+    session = await runner.session_service.create_session(
+        app_name=APP_NAME, user_id=USER_ID
+    )
+    # call agent with wrapper function "call_agent_async()"
+    await call_agent_async(
+        runner, USER_ID, session.id, "set state color to red"
+    )
+    # ... more agent calls ...
+    events_list = await call_agent_async(
+        runner, USER_ID, session.id, "update state color to blue"
+    )
+
+    # get invocation id
+    rewind_invocation_id=events_list[1].invocation_id
+
+    # rewind invocations (state color: red)
+    await runner.rewind_async(
+        user_id=USER_ID,
+        session_id=session.id,
+        rewind_before_invocation_id=rewind_invocation_id,
+    )
+    ```
+
+=== "Kotlin"
+
+    ```kotlin
+    --8<-- "examples/kotlin/snippets/sessions/RewindExample.kt:rewind_session"
+    ```
 
 When you call the ***rewind*** method, all ADK managed session-level resources
 are restored to the state they were in *before* the request you specified with

examples/kotlin/snippets/sessions/RewindExample.kt

@@ -0,0 +1,69 @@
+/*
+ * 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.
+ */
+
+package com.google.adk.kt.examples.sessions
+
+import com.google.adk.kt.agents.BaseAgent
+import com.google.adk.kt.events.Event
+import com.google.adk.kt.runners.InMemoryRunner
+import com.google.adk.kt.sessions.InMemorySessionService
+import com.google.adk.kt.sessions.SessionKey
+import com.google.adk.kt.types.Content
+import com.google.adk.kt.types.Part
+import com.google.adk.kt.types.Role
+import kotlinx.coroutines.flow.toList
+
+private const val APP_NAME = "rewind_app"
+private const val USER_ID = "user123"
+
+// --8<-- [start:rewind_session]
+suspend fun rewindSession(rootAgent: BaseAgent) {
+    val sessionService = InMemorySessionService()
+    val runner =
+        InMemoryRunner(agent = rootAgent, appName = APP_NAME, sessionService = sessionService)
+
+    // Create a session. The service assigns the id, which is held on Session.key.
+    val session = sessionService.createSession(SessionKey(APP_NAME, USER_ID, id = null))
+    val sessionId = checkNotNull(session.key.id)
+
+    // Call the agent
+    callAgent(runner, sessionId, "set state color to red")
+    // ... more agent calls ...
+    val events = callAgent(runner, sessionId, "update state color to blue")
+
+    // Get the invocation id of the request to undo
+    val rewindInvocationId = events[1].invocationId ?: return
+
+    // Rewind invocations (state color: red)
+    runner.rewindAsync(
+        userId = USER_ID,
+        sessionId = sessionId,
+        rewindBeforeInvocationId = rewindInvocationId,
+    )
+}
+
+private suspend fun callAgent(
+    runner: InMemoryRunner,
+    sessionId: String,
+    query: String,
+): List<Event> =
+    runner
+        .runAsync(
+            userId = USER_ID,
+            sessionId = sessionId,
+            newMessage = Content(role = Role.USER, parts = listOf(Part(text = query))),
+        ).toList()
+// --8<-- [end:rewind_session]

tools/kotlin-snippets/files_to_test.txt

@@ -40,3 +40,4 @@ snippets/tools/overview/UserPreferenceTools.kt
 snippets/tools/overview/CustomerSupport.kt
 snippets/tools/overview/DocAnalysisTools.kt
 snippets/tools/overview/OrderTools.kt
+snippets/sessions/RewindExample.kt