send the ``TRANSFER_ENCODING`` nor the ``HTTP_TRANSFER_ENCODING`` value to
the application in the environment. Instead, we pop this header. Since we
cope with chunked requests by buffering the data in the server, we also know
when a chunked request has ended, and therefore we know the content length.
We set the content-length header in the environment, such that applications
effectively never know the original request was a T-E: chunked request; it
will appear to them as if the request is a non-chunked request with an
accurate content-length.
- Cope with the fact that the ``Transfer-Encoding`` value is case-insensitive.
Fixes #43