Chunked Transfer Encoding - Applicability

Applicability

For version 1.1 of the HTTP protocol, the chunked transfer mechanism is considered to be always acceptable, even if not listed in the TE request header field, and when used with other transfer mechanisms, should always be applied last to the transferred data and never more than one time. This transfer coding method also allows additional entity header fields to be sent after the last chunk if the client specified the "trailers" parameter as an argument of the TE field. The origin server of the response can also decide to send additional entity trailers even if the client did not specify the "trailers" option in the TE request field, but only if the metadata is optional (i.e. the client can use the received entity without them). Whenever the trailers are used, the server should list their names in the Trailer header field; 3 header field types are specifically prohibited from appearing as a trailer field: Transfer-Encoding, Content-Length and Trailer.