Exchange attachments that have specific meaning when using the HTTP protocol
Attachment key for request trailers when using chunked encoding. When the request is parsed the trailers
will be attached under this key.
Attachment key for response trailers. If a header map is attached under this key then the contents will be written
out at the end of the chunked request.
Note that if pre chunked streams are being used then the trailers will not be appended to the response, however any
trailers parsed out of the chunked stream will be attached here instead.
If the value
is attached to the exchange under this key then Undertow will assume that the underlying application
has already taken care of chunking, and will not attempt to add its own chunk markers.
This will only take effect if the application has explicitly set the Transfer-Encoding: chunked) header.