eds: optionalize counting of unknown fields (#10982)

In order to speed up eds, don't necessarily visit every proto field to count its validity as WarningValidationVisitor does. This yields a ~30% speed improvement in processing very large updates in EDS.

Risk Level: medium, new feature behind a command line flag.
Testing: Unit and bechmark tests.
Docs Changes: These are probably wrong, thus the draft-ness.
Release Notes: EDS can now ignore unknown dynamic fields, for a ~30% improvement in update processing time. Behind --ignore-unknown-dynamic-fields

Co-authored-by: Joshua Marantz <jmarantz@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 703f2fbdd4d2b11db901a74d15726bc6c017189b

envoy/admin/v3/server_info.proto

@@ -54,7 +54,7 @@ message ServerInfo {
   CommandLineOptions command_line_options = 6;
 }
 
-// [#next-free-field: 30]
+// [#next-free-field: 31]
 message CommandLineOptions {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.admin.v2alpha.CommandLineOptions";
@@ -97,6 +97,9 @@ message CommandLineOptions {
   // See :option:`--reject-unknown-dynamic-fields` for details.
   bool reject_unknown_dynamic_fields = 26;
 
+  // See :option:`--ignore-unknown-dynamic-fields` for details.
+  bool ignore_unknown_dynamic_fields = 30;
+
   // See :option:`--admin-address-path` for details.
   string admin_address_path = 6;
 

envoy/admin/v4alpha/server_info.proto

@@ -54,7 +54,7 @@ message ServerInfo {
   CommandLineOptions command_line_options = 6;
 }
 
-// [#next-free-field: 30]
+// [#next-free-field: 31]
 message CommandLineOptions {
   option (udpa.annotations.versioning).previous_message_type = "envoy.admin.v3.CommandLineOptions";
 
@@ -96,6 +96,9 @@ message CommandLineOptions {
   // See :option:`--reject-unknown-dynamic-fields` for details.
   bool reject_unknown_dynamic_fields = 26;
 
+  // See :option:`--ignore-unknown-dynamic-fields` for details.
+  bool ignore_unknown_dynamic_fields = 30;
+
   // See :option:`--admin-address-path` for details.
   string admin_address_path = 6;