Add broker timestamps to authentication response, improving request tracking

Author: prsaminathan

common/src/main/java/com/microsoft/identity/common/adal/internal/AuthenticationConstants.java

@@ -1563,6 +1563,16 @@ public static String computeMaxHostBrokerProtocol() {
          */
         public static final String BROKER_APP_LINK_REDIRECT_URL_PATH_PREFIX = "androidbroker";
 
+        /**
+         * Timestamp when the broker received the authentication request.
+         */
+        public static final String BROKER_REQUEST_RECEIVED_TIMESTAMP = "broker_request_received_timestamp";
+
+        /**
+         * Timestamp when the broker generated the authentication response.
+         */
+        public static final String BROKER_RESPONSE_GENERATION_TIMESTAMP = "broker_response_generation_timestamp";
+
         /**
          * Bundle identifiers for x-ms-clitelem info.
          */