- HEADERFUNCTIONS might inspect response properties like
CURLINFO_CONTENT_LENGTH_DOWNLOAD_T on seeing the last header line. If
the line is being written before this is initialized, values are not
available.
- write the last header line late when analyzing a HTTP response so that
all information is available at the time of the writing.
- add test1485 to verify that CURLINFO_CONTENT_LENGTH_DOWNLOAD_T works
on seeing the last header.
Fixes#13752
Reported-by: Harry Sintonen
Closes#13757