'Convenience method for setting both `stream` and `stream_len`.
Although the `stream` and `stream_len` properties may be set
directly, using this method ensures `stream_len` is not
accidentally neglected when the length of the stream is known in
advance.
Note:
If the stream length is unknown, you can set `stream`
directly, and ignore `stream_len`. In this case, the
WSGI server may choose to use chunked encoding or one
of the other strategies suggested by PEP-3333.'

def set_stream(self, stream, stream_len):

    self.stream = stream
    self.stream_len = stream_len
