The signature of parse_header, body_qs, multipart_data and the set_resp_* functions has changed. See the cowboy_req module edoc for more details.
Pretty much just an alias for a combination of set_resp_header and cookie.
These functions allow to set response headers and body in advance, before calling any of the reply functions. Also add has_resp_header/2 and has_resp_body/1 to check if the given response headers have already been set.
