Clarify proxy_action_t values about spec HOT 3 CLOSED

Extra info: since my authorizer is looking at the client TLS principal, it has to happen in proxy_on_downstream_data handler now since the proxy_on_new_connection one fires when the TCP connection is made before the TLS handshake (which makes sense as you may want to intercept the handshake too). Both of these handlers are limited to only returning Continue or Pause/StopIterarion currently though so it would seem there is no option to RST the connection from a filter currently?

from spec.

I am also trying to understand how to read this. I see proxy_on_http_request_body returns i32 (proxy_action_t) next_action.

I suspect the actions are the enumerations defined in https://github.com/envoyproxy/envoy/blob/master/include/envoy/http/filter.h . Including the enumerations in the spec would help.

I suspect functions must abide by the same contract as Envoy extensions, e.g. the rules mentioned in https://www.envoyproxy.io/docs/envoy/latest/faq/extensions/contract.html#is-there-a-contract-my-http-filter-must-adhere-to . This is also not spelled out.

I have looked at native Envoy filter source code but never written one. The spec should incorporate, by value or by reference, sufficient information on enumerations and on state management.

from spec.

I believe this will be resolved by our project overhaul. Please refer to #39 (comment) for the context. Thanks!

from spec.