add AsyncExitStack examples

README.rst

@@ -83,6 +83,48 @@ Basic Example
     loop.run_until_complete(go())
 
 
+
+Context Manager Examples
+------------------------
+
+.. code:: python
+
+    from contextlib import AsyncExitStack
+    from typing import
+    
+    import aiobotocore.session
+    
+    
+    # How to use in existing context manager
+    class Manager:
+        def __init__(self):
+            self._exit_stack = AsyncExitStack()
+            self._s3_client = None
+    
+        async def __aenter__(self):
+            session = aiobotocore.session.AioSession()
+            self._s3_client = await self._exit_stack.enter_async_context(session.create_client('s3'))
+    
+        async def __aexit__(self, exc_type, exc_val, exc_tb):
+            await self._exit_stack.__aexit__(exc_type, exc_val, exc_tb)
+    
+    # How to use with an external exit_stack
+    async def create_s3_client(session: aiobotocore.session.AioSession, exit_stack: AsyncExitStack):
+        # Create client and add cleanup
+        client = await exit_stack.enter_async_context(session.create_client('s3'))
+        return client
+    
+    
+    async def non_manager_example():
+        session = aiobotocore.session.AioSession()
+    
+        async with AsyncExitStack() as exit_stack:
+            s3_client = await create_s3_client(session, exit_stack)
+    
+            # do work with s3_client
+
+
+
 Supported AWS Services
 ----------------------