http: add downstream remote reset response flag (#32623)

* add dr response flag

Signed-off-by: Boteng Yao <boteng@google.com>

* add tests

Signed-off-by: Boteng Yao <boteng@google.com>

* fix assertion

Signed-off-by: Boteng Yao <boteng@google.com>

* fix format

Signed-off-by: Boteng Yao <boteng@google.com>

* fix proto

Signed-off-by: Boteng Yao <boteng@google.com>

* fix test

Signed-off-by: Boteng Yao <boteng@google.com>

* fix test

Signed-off-by: Boteng Yao <boteng@google.com>

* add change logs

Signed-off-by: Boteng Yao <boteng@google.com>

---------

Signed-off-by: Boteng Yao <boteng@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 0cb0b01b7f44399085e511085e51e8222132982e

envoy/config/accesslog/v3/accesslog.proto

@@ -256,6 +256,7 @@ message ResponseFlagFilter {
         in: "OM"
         in: "DF"
         in: "DO"
+        in: "DR"
       }
     }
   }];

envoy/data/accesslog/v3/accesslog.proto

@@ -271,7 +271,7 @@ message AccessLogCommon {
 }
 
 // Flags indicating occurrences during request/response processing.
-// [#next-free-field: 28]
+// [#next-free-field: 29]
 message ResponseFlags {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.data.accesslog.v2.ResponseFlags";
@@ -372,6 +372,9 @@ message ResponseFlags {
 
   // Indicates a DNS resolution failed.
   bool dns_resolution_failure = 27;
+
+  // Indicates a downstream remote codec level reset was received on the stream
+  bool downstream_remote_reset = 28;
 }
 
 // Properties of a negotiated TLS connection.