easy:SetOpt_HSTS(filename)
filename to a file name to load an existing HSTS cache
from, and to store the cache in when the easy handle is closed. Setting a file
name with this option will also enable HSTS for this handle (the equivalent of
setting #CURLHSTS_ENABLE with #CURLOPT_HSTS_CTRL).
If the given file does not exist or contains no HSTS entries at startup, the
HSTS cache will simply start empty. Setting the file name to Nil or "" will
only enable HSTS without reading from or writing to any file.
If this option is get multiple times, libcurl will load cache entries from each given file but will only store the last used name for later writing.