ReWriteMap or http headers to set in response headers

[venukbh]

I read the upcoming features of 3.1 would be ReWriteMap implementation. However, I could not see any implementations or examples for it. Also searching through the project, comments say "to be implemented". So is ReWriteMap functionality implemented?

Also, is there a way to access the http_headers like origin or referer in the response header? When ever I try to set them using %{origin} in response-header, I always get error key not found. But the same can be accessed in condition tag. Please suggest if there is any solution.