MCPServerStdio has no response

Thanks, I found this repro pretty helpful to get started with MCP and anzure ai portal.

Currently I stuck in
async with MCPServerStdio(
name="Filesystem Server, via npx",
params={
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-filesystem", samples_dir],
},
) as server:
print("MCPServerStdio 已启动")
await run(server）

There is not any input and nor do exception happened, it just no response.
Still trying to work it out, do anyone know why?