added Server-Timing header nginx level

config/nginx/onlyoffice.conf

@@ -54,6 +54,16 @@ map $request_uri $content_security_policy {
         ~*\/(ds-vpath)\/ "default-src *; script-src * 'unsafe-inline' 'unsafe-eval'; script-src-elem * 'unsafe-inline'; img-src * data:; style-src * 'unsafe-inline' data:; font-src * data:; frame-src * ascdesktop:; object-src; connect-src * ascdesktop:;";
 }
 
+map $request_time $request_time_ms {
+    # Simple case for 0.000
+    ~^0\.000$ 0;
+    # If 0 before decimal place, must remove leading zeros after it
+    ~^0\.(?:0*)([^0].*)$ $1;
+    # Otherwise just concatenate the full pre- & post-decimal parts
+    ~^([^0][^.]*)\.(.*)$ $1$2;
+}
+
+
 include /etc/nginx/includes/onlyoffice-*.conf;
 
 server_names_hash_bucket_size 128;
@@ -288,6 +298,9 @@ server {
 	}
 
 	location /api/2.0 {
+        add_header Trailer Server-Timing;
+        add_header Server-Timing "http.server-request-time;dur=${request_time_ms}";
+
 		location ~* /(files|privacyroom) {
 			 proxy_pass http://127.0.0.1:5007;
 		}