Disk cache protocol isn't supported by CWF

[lisupeng]

Thanks for your great work!
I used CWF in my opensource online wiki/doc and collaboration project Tsailun - https://github.com/lisupeng/tsailun

I found CWF won't use the disk cache protocol.

Below is the details:

1. browser request a file - aaa.jpg
2. refresh page, CWF will resend whole data of aaa.jpg instead of file not changed message. This behavior is different from nginx/apache.

This feature can avoid a lot traffic and takes fewer time to display a web page.
Do you have plan to support this feature ?

[lisupeng]

wireshark captured packets