The filename desired for the object, if nexml is not already a file.
if the first argument is already a path, this value is ignored.
categories
The figshare categories, must match available set. see fs_add_categories
tags
Any keyword tags you want to add to the data.
visibility
whether the results should be published (public), or kept private,
or kept as a draft for further editing before publication. (New versions can be updated,
but any former versions that was once made public will always be archived and cannot be removed).
id
an existing figshare id (e.g. from fs_create), to which this file can be appended.