Invoke call.close only if call was not cancelled

[mopfattn]

trafficstars

We experienced an issue with streaming responses. When we have multiple active requests and one of the requests is cancelled by the client, then all other requests are also closed.

It appears that invoking call.close an a cancelled call somehow affects the established http connection which is then closed by the http server.

[linux-foundation-easycla[bot]]

• :white_check_mark:login: mopfattn / (36453769b03c6282acbe53523054aa4f2024e428)

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[duckladydinh]

This PR somehow doesn't trigger test. Is this still an issue? If yes, can you try rebase it into the main branch?