Add method to create MessageHeaders in Message

spring-context/src/main/java/org/springframework/messaging/GenericMessage.java

@@ -64,11 +64,15 @@ public class GenericMessage<T> implements Message<T>, Serializable {
 		else {
 			headers = new HashMap<String, Object>(headers);
 		}
-		this.headers = new MessageHeaders(headers);
+		this.headers = createMessageHeaders(headers);
 		this.payload = payload;
 	}
 
 
+	protected MessageHeaders createMessageHeaders(Map<String, Object> headers) {
+		return new MessageHeaders(headers);
+	}
+
 	public MessageHeaders getHeaders() {
 		return this.headers;
 	}