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)
For most files we download we know the exact size beforehand (because
this information comes from the snapshot or delegated info)