CURLOPT_TRANSFER_ENCODING man page
CURLOPT_TRANSFER_ENCODING — ask for HTTP Transfer Encoding
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TRANSFER_ENCODING, long enable);
Pass a long set to 1 to enable or 0 to disable.
Adds a request for compressed Transfer Encoding in the outgoing HTTP request. If the server supports this and so desires, it can respond with the HTTP response sent using a compressed Transfer-Encoding that will be automatically uncompressed by libcurl on reception.
Transfer-Encoding differs slightly from the Content-Encoding you ask for with CURLOPT_ACCEPT_ENCODING(3) in that a Transfer-Encoding is strictly meant to be for the transfer and thus MUST be decoded before the data arrives in the client. Traditionally, Transfer-Encoding has been much less used and supported by both HTTP clients and HTTP servers.
Added in 7.21.6
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.