Indicate if the proxy server timed out

[Chris7]

Is your proposal related to a problem?

I spent about an hour or so trying to debug why my backend was severing a connection to the frontend locally

Proxy error: Could not proxy request /graphql/ from localhost:3000 to http://localhost:8080.
See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (ECONNRESET).

Eventually, I figured out it's because of a timeout in the proxy (#3210). It would be very helpful to indicate that the proxy is resetting the connection so users don't needlessly try to debug their server settings.

Describe the solution you'd like

Provide an indication the connection being reset was done by the proxy. At the moment, it's identical if the backend server reset it.