Is there a way to have libraw extract the metadata from a RAW file without unpacking all the data?

I'm using the libraw plug-in that is part of OpenImageIO. In that plugin, unpack() is called before any of the image properties are read, which causes the property reading to be incredibly slow because unpacking() is slow (relative to just reading the TIFF header in most RAW files.)

https://github.com/OpenImageIO/oiio/blob/master/src/raw.imageio/rawinput...

Can unpack() be skipped and the headers still be read correctly? What about the other values like image dimensions?