Removes unused variable

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/factory/rewrite/ModifyResponseBodyGatewayFilterFactory.java

@@ -98,7 +98,6 @@ public class ModifyResponseBodyGatewayFilterFactory
 					CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, exchange.getResponse().getHeaders());
 					return bodyInserter.insert(outputMessage, new BodyInserterContext())
 							.then(Mono.defer(() -> {
-								long contentLength1 = getDelegate().getHeaders().getContentLength();
 								Flux<DataBuffer> messageBody = outputMessage.getBody();
 								//TODO: if (inputStream instanceof Mono) {
 									HttpHeaders headers = getDelegate().getHeaders();