Response leak in SSE handlers

I found a resource leak in the streamable HTTP client. When SSE streaming fails with an exception, the HTTP response isn't closed.

Location:
src/mcp/client/streamable_http.py:

• _handle_sse_response (line 336)
• _handle_resumption_request (line 251)

The Issue:
python
async def _handle_sse_response(self, response: httpx.Response, ...):
try:
event_source = EventSource(response)
async for sse in event_source.aiter_sse():
if is_complete:
await response.aclose() # Only closed here
break
except Exception as e:
await ctx.read_stream_writer.send(e)
# response leaked!

If the SSE iteration raises an exception (malformed JSON, network error, etc.), the response is never closed.

Impact:
Connection pool gets exhausted in long-running clients, eventually causing new requests to hang or fail.

Fix:
try:
...
except Exception as e:
...
finally:
await response.aclose()

Both methods need this fix.

Env:
Python SDK version: 1.1.2 (or main branch)
Python: 3.12
Transport: StreamableHTTP

Lisez src/mcp/client/streamable_http.py, en vous concentrant sur _handle_sse_response et _handle_resumption_request. Suivez la manière dont chaque méthode gère l’itération SSE et les exceptions, puis vérifiez que les deux chemins ferment la réponse HTTP aussi bien après des échecs qu’après une fin normale.