Allow for async use of SelfAskWithSearchChain (#5394)

# Allow for async use of SelfAskWithSearchChain


Co-authored-by: Dev 2049 <dev.dev2049@gmail.com>

langchain/agents/self_ask_with_search/base.py

@@ -77,7 +77,10 @@ class SelfAskWithSearchChain(AgentExecutor):
     ):
         """Initialize with just an LLM and a search chain."""
         search_tool = Tool(
-            name="Intermediate Answer", func=search_chain.run, description="Search"
+            name="Intermediate Answer",
+            func=search_chain.run,
+            coroutine=search_chain.arun,
+            description="Search",
         )
         agent = SelfAskWithSearchAgent.from_llm_and_tools(llm, [search_tool])
         super().__init__(agent=agent, tools=[search_tool], **kwargs)