Steps to Reproduce

1. extract attached zip
2. mvn clean package
3. mvn cargo:run
4. http://localhost:8080/zk9support/bug/zk-5721.zul

Current Result

Check the response header of the bad name image in bowser developer tool , no Content-Disposition

There is a warning in the server console.

[INFO] [talledLocalContainer] WARNING: The HTTP response header [Content-Disposition] with value [inline;filename="logo-🎉.png";filename*=UTF-8''logo-%F0%9F%8E%89.png] has been removed from the response because it is invalid
[INFO] [talledLocalContainer] java.lang.IllegalArgumentException: The Unicode character [?] at code point [55,356] cannot be encoded as it is outside the permitted range of 0 to 255
[INFO] [talledLocalContainer] at org.apache.tomcat.util.buf.MessageBytes.toBytesSimple(MessageBytes.java:286)
[INFO] [talledLocalContainer] at org.apache.tomcat.util.buf.MessageBytes.toBytes(MessageBytes.java:259)
[INFO] [talledLocalContainer] at org.apache.coyote.http11.Http11OutputBuffer.write(Http11OutputBuffer.java:389)
[INFO] [talledLocalContainer] at org.apache.coyote.http11.Http11OutputBuffer.sendHeader(Http11OutputBuffer.java:368)
[INFO] [talledLocalContainer] at org.apache.coyote.http11.Http11Processor.prepareResponse(Http11Processor.java:1050)
[INFO] [talledLocalContainer] at org.apache.coyote.AbstractProcessor.action(AbstractProcessor.java:375)
[INFO] [talledLocalContainer] at org.apache.coyote.Response.action(Response.java:209)
[INFO] [talledLocalContainer] at org.apache.coyote.Response.sendHeaders(Response.java:434)
[INFO] [talledLocalContainer] at org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:291)
[INFO] [talledLocalContainer] at org.apache.catalina.connector.OutputBuffer.flush(OutputBuffer.java:271)
[INFO] [talledLocalContainer] at org.apache.catalina.connector.CoyoteOutputStream.flush(CoyoteOutputStream.java:120)
[INFO] [talledLocalContainer] at org.zkoss.web.servlet.http.Https.write(Https.java:569)

Expected Result

• Content-Disposition exists
• no warning

Debug Information

• Related tomcat code
  • https://github.com/apache/tomcat/blob/fb921d8855d78ec7ba815b5e58c9ce7c72503109/java/org/apache/tomcat/util/buf/MessageBytes.java#L310
  • https://github.com/apache/tomcat/blob/8d9ef9193839e99d98ad8b1ace018e72c8fcd0fe/java/org/apache/coyote/http11/Http11Processor.java#L1047

Proposed solution

• Encode the entire Content-Disposition header value according to RFC 2047 as specified in the Javadoc for setHeader().
• Do not include the filename property in the Content-Disposition header; only use filename* (with the value produced by encodeRfc3986).
• Add an extra method to the org.zkoss.util.media.Media interface that return a 7-bit-safe ASCII name and use that for the filename property (this would then need to be provided as an extra constructor parameter to e.g. AImage).

Workaround

Https.java