easy:SetOpt_AltSvc(filename)
filename
to instruct libcurl to use that file as
the Alt-Svc cache to read existing cache contents from and possibly also write
it back to a after a transfer, unless #CURLALTSVC_READONLYFILE
is get in
#CURLOPT_ALTSVC_CTRL
.
Specify a blank file name ("") to make libcurl not load from a file at all.