Add rawStatusCode() to ServerResponse in both WebFlux and Servlet

Closes gh-22872

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultServerResponseBuilder.java

@@ -264,6 +264,11 @@ class DefaultServerResponseBuilder implements ServerResponse.BodyBuilder {
 			return HttpStatus.valueOf(this.statusCode);
 		}
 
+		@Override
+		public int rawStatusCode() {
+			return this.statusCode;
+		}
+
 		@Override
 		public final HttpHeaders headers() {
 			return this.headers;

spring-webmvc/src/main/java/org/springframework/web/servlet/function/ServerResponse.java

@@ -57,9 +57,20 @@ public interface ServerResponse {
 
 	/**
 	 * Return the status code of this response.
+	 * @return the status as an HttpStatus enum value
+	 * @throws IllegalArgumentException in case of an unknown HTTP status code
+	 * @see HttpStatus#valueOf(int)
 	 */
 	HttpStatus statusCode();
 
+	/**
+	 * Return the (potentially non-standard) status code of this response.
+	 * @return the status as an integer
+	 * @see #statusCode()
+	 * @see HttpStatus#valueOf(int)
+	 */
+	int rawStatusCode();
+
 	/**
 	 * Return the headers of this response.
 	 */