Support different transports in Client (#1972)

examples/clients/sse-polling-client/mcp_sse_polling_client/main.py

@@ -31,7 +31,7 @@ async def run_demo(url: str, items: int, checkpoint_every: int) -> None:
     print(f"Processing {items} items with checkpoints every {checkpoint_every}")
     print(f"{'=' * 60}\n")
 
-    async with streamable_http_client(url) as (read_stream, write_stream, _):
+    async with streamable_http_client(url) as (read_stream, write_stream):
         async with ClientSession(read_stream, write_stream) as session:
             # Initialize the connection
             print("Initializing connection...")