Revert "enable to will_continue-like function response in BaseLlmFlow.run_async method."

This reverts commit e683005.

Author: hachiya-takuya

src/google/adk/flows/llm_flows/base_llm_flow.py

@@ -466,18 +466,16 @@ async def _postprocess_handle_function_calls_async(
       function_call_event: Event,
       llm_request: LlmRequest,
   ) -> AsyncGenerator[Event, None]:
-    if function_response_event_generator := await functions.handle_function_calls_async(
+    if function_response_event := await functions.handle_function_calls_async(
         invocation_context, function_call_event, llm_request.tools_dict
     ):
-      async for function_response_event in function_response_event_generator:
-        auth_event = functions.generate_auth_event(
-            invocation_context, function_response_event
-        )
-        if auth_event:
-          yield auth_event
-
-        yield function_response_event
+      auth_event = functions.generate_auth_event(
+          invocation_context, function_response_event
+      )
+      if auth_event:
+        yield auth_event
 
+      yield function_response_event
       transfer_to_agent = function_response_event.actions.transfer_to_agent
       if transfer_to_agent:
         agent_to_run = self._get_agent_to_run(

src/google/adk/flows/llm_flows/functions.py

@@ -128,17 +128,17 @@ async def handle_function_calls_async(
     function_call_event: Event,
     tools_dict: dict[str, BaseTool],
     filters: Optional[set[str]] = None,
-) -> AsyncGenerator[Opeional[Event], None]:
+) -> Optional[Event]:
   """Calls the functions and returns the function response event."""
   from ...agents.llm_agent import LlmAgent
 
   agent = invocation_context.agent
   if not isinstance(agent, LlmAgent):
-    yield None
     return
 
   function_calls = function_call_event.get_function_calls()
 
+  function_response_events: list[Event] = []
   for function_call in function_calls:
     if filters and function_call.id not in filters:
       continue
@@ -217,51 +217,33 @@ async def handle_function_calls_async(
         if not function_response:
           continue
 
-      function_response_events: list[Event] = []
-      async for function_response_one in _ensure_async_generator_function_response(
-              function_response
-      ):
-        # Builds the function response event.
-        function_response_event = __build_response_event(
-            tool, function_response_one, tool_context, invocation_context
-        )
-        trace_tool_call(
-            tool=tool,
-            args=function_args,
-            function_response_event=function_response_event,
-        )
-        function_response_events.append(function_response_event)
+      # Builds the function response event.
+      function_response_event = __build_response_event(
+          tool, function_response, tool_context, invocation_context
+      )
+      trace_tool_call(
+          tool=tool,
+          args=function_args,
+          function_response_event=function_response_event,
+      )
+      function_response_events.append(function_response_event)
 
-        if not function_response_events:
-          yield None
-          return
-        merged_event = merge_parallel_function_response_events(
-            function_response_events
-        )
-        if len(function_response_events) > 1:
-          # this is needed for debug traces of parallel calls
-          # individual response with tool.name is traced in __build_response_event
-          # (we drop tool.name from span name here as this is merged event)
-          with tracer.start_as_current_span('execute_tool (merged)'):
-            trace_merged_tool_calls(
-                response_event_id=merged_event.id,
-                function_response_event=merged_event,
-            )
-        yield merged_event
-
-
-
-async def _ensure_async_generator_function_response(
-        function_response: Union[str, dict, AsyncGenerator]
-) -> AsyncGenerator[Opeional[Event], None]:
-    if inspect.isasyncgen(function_response):
-        async for response in function_response:
-            yield response
-    elif inspect.isgenerator(function_response):
-        for response in function_response:
-            yield response
-    else:
-        yield function_response
+  if not function_response_events:
+    return None
+  merged_event = merge_parallel_function_response_events(
+      function_response_events
+  )
+
+  if len(function_response_events) > 1:
+    # this is needed for debug traces of parallel calls
+    # individual response with tool.name is traced in __build_response_event
+    # (we drop tool.name from span name here as this is merged event)
+    with tracer.start_as_current_span('execute_tool (merged)'):
+      trace_merged_tool_calls(
+          response_event_id=merged_event.id,
+          function_response_event=merged_event,
+      )
+  return merged_event
 
 
 async def handle_function_calls_live(