Merge pull request #32141 from kzander91

* pr/32141:
  Polish "Simplify use of Reactor's cast operator"
  Simplify use of Reactor's cast operator

Closes gh-32141

spring-web/src/main/java/org/springframework/http/codec/multipart/PartEventHttpMessageReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -167,9 +167,8 @@ public class PartEventHttpMessageReader extends LoggingCodecSupport implements H
 									Assert.state(headersToken != null, "Signal should be headers token");
 
 									HttpHeaders headers = headersToken.headers();
-									Flux<MultipartParser.BodyToken> bodyTokens =
-											flux.filter(t -> t instanceof MultipartParser.BodyToken)
-													.cast(MultipartParser.BodyToken.class);
+									Flux<MultipartParser.BodyToken> bodyTokens = flux.ofType(
+											MultipartParser.BodyToken.class);
 									return createEvents(headers, bodyTokens);
 								}
 								else {

spring-webflux/src/test/java/org/springframework/web/reactive/function/MultipartRouterFunctionIntegrationTests.java

@@ -240,9 +240,8 @@ class MultipartRouterFunctionIntegrationTests extends AbstractRouterFunctionInte
 
 		public Mono<ServerResponse> transferTo(ServerRequest request) {
 			return request.body(BodyExtractors.toParts())
-					.filter(FilePart.class::isInstance)
+					.ofType(FilePart.class)
 					.next()
-					.cast(FilePart.class)
 					.flatMap(part -> createTempFile()
 							.flatMap(tempFile ->
 									part.transferTo(tempFile)