No knowledge of the data stream outside the currently-being-processed chunk is necessary for both the sender and the receiver at any given time.
Chunked transfer encoding is not supported in HTTP/2, which provides its own mechanisms for data streaming.
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).
These parameters could be used for a running message digest or digital signature, or to indicate an estimated transfer progress, for instance.
It may contain a trailer, which consists of a (possibly empty) sequence of entity header fields.
The remote endpoint then decodes the stream by concatenating the chunks and uncompressing the result.