Function write 

pub fn write(
    design: &Design,
    attachments: &[Attachment],
) -> Result<Imported<Vec<u8>>, OrkError>

A .ork file for design: a zip archive holding its document as rocket.ork, and then attachments, such as the thrust curves and preview image of the file it was read from (super::OrkFile::attachments). An attachment called rocket.ork is left out, with a warning: the design is that entry.

Errors

OrkError::Zip if the archive cannot be written, which in memory means an attachment’s name is one no zip entry can have.