Size of the file in bytes. If this file is a symbolic link the size is
the length of the pathname it contains.
Set to 0 if unknown or a directory
Size of the file in bytes. Does not follow symlinks
Get size of a file in the archive.
File size in bytes.
attribute represented as a Natural
Get size of a file in the archive (by index).
For some files we might not know the size beforehand, but we might be
able to provide an upper bound (timestamp, root info)