Jetty 9.4.3.v20170317 refuses to set an empty HTTP header, leading to cryptic...

Jetty 9.4.3.v20170317 refuses to set an empty HTTP header, leading to cryptic client errors since Hudson-Duplex is missing.

core/src/main/java/jenkins/util/FullDuplexHttpService.java

@@ -153,7 +153,7 @@ public abstract class FullDuplexHttpService {
                 // the actual authentication for the connecting Channel is done by CLICommand
 
                 UUID uuid = UUID.fromString(req.getHeader("Session"));
-                rsp.setHeader("Hudson-Duplex", ""); // set the header so that the client would know
+                rsp.setHeader("Hudson-Duplex", "true"); // set the header so that the client would know
 
                 if (req.getHeader("Side").equals("download")) {
                     FullDuplexHttpService service = createService(req, uuid);