Refine onError handling WebAsyncManager

In addition to the wrapping of errors recognized as client disconnected
errors with AsyncRequestNotUsableException, we now wrap any IOException
in the onError callback. The Servlet container would only be aware of
such an exception if it relates to the response.

Closes gh-33832

spring-web/src/main/java/org/springframework/web/context/request/async/WebAsyncManager.java

@@ -16,6 +16,7 @@
 
 package org.springframework.web.context.request.async;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -34,7 +35,6 @@ import org.springframework.core.task.SimpleAsyncTaskExecutor;
 import org.springframework.util.Assert;
 import org.springframework.web.context.request.RequestAttributes;
 import org.springframework.web.context.request.async.DeferredResult.DeferredResultHandler;
-import org.springframework.web.util.DisconnectedClientHelper;
 
 /**
  * The central class for managing asynchronous request processing, mainly intended
@@ -343,7 +343,7 @@ public final class WebAsyncManager {
 			if (logger.isDebugEnabled()) {
 				logger.debug("Servlet container error notification for " + formatUri(this.asyncWebRequest) + ": " + ex);
 			}
-			if (DisconnectedClientHelper.isClientDisconnectedException(ex)) {
+			if (ex instanceof IOException) {
 				ex = new AsyncRequestNotUsableException(
 						"Servlet container error notification for disconnected client", ex);
 			}
@@ -439,7 +439,7 @@ public final class WebAsyncManager {
 			if (logger.isDebugEnabled()) {
 				logger.debug("Servlet container error notification for " + formatUri(this.asyncWebRequest));
 			}
-			if (DisconnectedClientHelper.isClientDisconnectedException(ex)) {
+			if (ex instanceof IOException) {
 				ex = new AsyncRequestNotUsableException(
 						"Servlet container error notification for disconnected client", ex);
 			}