Enable to close tcp socket for stale websocket connection

## What is the problem your feature solves, or the need it fulfills?

In the proxy mode, we can choose different peer as we need. but if the old peer is considered as unhealthy and port still alive. in this case the upstream connection won't be close, neither do downstream. The stale websocket tcp connection won't be dropped. The downstream keeps the connection but can't receive any update.

## Describe the solution you'd like

in the ProxyHttp or some other tracer expose some method, which we can send signal to ask the backend force close the tcp stream.

## Describe alternatives you've considered

A workaround we have use right now is to collect underlying tcp connection, and use libc to force close tcp fd as we need.