config: recommended_metrics - Add proxy_session_established to @metric_defaults=proxy

Author: sirainen

data/updates.js

@@ -58,6 +58,7 @@ export const updates = {
 	mail_crypt_fs_maybe: '2.4.0',
 	mail_location_keep_noselect: '2.4.0',
 	mail_location_no_noselect: '2.4.0',
+	metric_defaults_proxy_session_established_added: '2.4.2',
 	metric_group_by_discrete_modifiers_added: '2.4.0',
 	migration_imapc_features: '2.4.0',
 	namespace_prefix_shared_variables_changed: '2.4.0',

docs/core/config/recommended_metrics_include/proxy.inc

@@ -14,3 +14,9 @@
 
 `login_aborted`
 :  Number of aborted logins, grouped by reason. See [[event,login_aborted]].
+
+`proxy_session_established`
+:  [[added,metric_defaults_proxy_session_established_added]] Number of
+   successful proxy sessions. This can be used to see post-authentication
+   latency until session is logged into a backend. See
+   [[event,proxy_session_established]].