refactor: Creating a long term Runner.runAsyncImpl

PiperOrigin-RevId: 869400120

Author: google-genai-bot

core/src/main/java/com/google/adk/runner/Runner.java

@@ -381,7 +381,7 @@ public Flowable<Event> runAsync(
                       new IllegalArgumentException(
                           String.format("Session not found: %s for user %s", sessionId, userId)));
                 }))
-        .flatMapPublisher(session -> this.runAsync(session, newMessage, runConfig, stateDelta));
+        .flatMapPublisher(session -> this.runAsyncImpl(session, newMessage, runConfig, stateDelta));
   }
 
   /** See {@link #runAsync(String, String, Content, RunConfig, Map)}. */
@@ -415,6 +415,23 @@ public Flowable<Event> runAsync(
       Content newMessage,
       RunConfig runConfig,
       @Nullable Map<String, Object> stateDelta) {
+    return runAsyncImpl(session, newMessage, runConfig, stateDelta);
+  }
+
+  /**
+   * Runs the agent asynchronously using a provided Session object.
+   *
+   * @param session The session to run the agent in.
+   * @param newMessage The new message from the user to process.
+   * @param runConfig Configuration for the agent run.
+   * @param stateDelta Optional map of state updates to merge into the session for this run.
+   * @return A Flowable stream of {@link Event} objects generated by the agent during execution.
+   */
+  protected Flowable<Event> runAsyncImpl(
+      Session session,
+      Content newMessage,
+      RunConfig runConfig,
+      @Nullable Map<String, Object> stateDelta) {
     Span span =
         Tracing.getTracer().spanBuilder("invocation").setParent(Context.current()).startSpan();
     Context spanContext = Context.current().with(span);
@@ -688,6 +705,7 @@ public Flowable<Event> runLive(
    *
    * @return stream of generated events.
    */
+  @Deprecated(since = "0.5.0", forRemoval = true)
   public Flowable<Event> runWithSessionId(
       String sessionId, Content newMessage, RunConfig runConfig) {
     // TODO(b/410859954): Add user_id to getter or method signature. Assuming "tmp-user" for now.