Cannot explicitly set POST headers and body

Hi,

Basically I would like to set the body with the XML I constructed and set the content type to "application/xml". However, with the existing API, I just could not figure out how to explicitly set the headers and body for POST message.

resp = myendpoint.update().post(payload=":",
headers={"Content-Type":"text/xml"})

which always converted my request into a html form submission.

Finally I have to resort to a quick hack to make it work.

https://github.com/hsun/apibee/commit/7bc5310b94f0cb817f97efccf2201c85b3b5b1dc

Maybe there is a more elegant way to do it?

-thanks