Size of the file in bytes. If this file is a symbolic link the size is
the length of the pathname it contains.
Size of the file in bytes. Does not follow symlinks
File size in bytes.
attribute represented as a Natural
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)
For a handle hdl
which attached to a physical file,
returns the size of that file in 8-bit