Trim decoded SSE data

Fixes #22043

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -119,21 +119,21 @@ public class ServerSentEventHttpMessageReader implements HttpMessageReader<Objec
 		for (String line : lines) {
 			if (line.startsWith("data:")) {
 				data = (data != null ? data : new StringBuilder());
-				data.append(line.substring(5)).append("\n");
+				data.append(line.substring(5).trim()).append("\n");
 			}
 			if (shouldWrap) {
 				if (line.startsWith("id:")) {
-					sseBuilder.id(line.substring(3));
+					sseBuilder.id(line.substring(3).trim());
 				}
 				else if (line.startsWith("event:")) {
-					sseBuilder.event(line.substring(6));
+					sseBuilder.event(line.substring(6).trim());
 				}
 				else if (line.startsWith("retry:")) {
-					sseBuilder.retry(Duration.ofMillis(Long.valueOf(line.substring(6))));
+					sseBuilder.retry(Duration.ofMillis(Long.valueOf(line.substring(6).trim())));
 				}
 				else if (line.startsWith(":")) {
 					comment = (comment != null ? comment : new StringBuilder());
-					comment.append(line.substring(1)).append("\n");
+					comment.append(line.substring(1).trim()).append("\n");
 				}
 			}
 		}