OptionalfetchedThe URL the bytes were fetched from, for a picture the workbook keeps for it.
OptionalnameThe name of the resource. This is optional and purely for human consumption and is not used by the system.
An encoding for the resource. One and only of these should be provided
When adding a shared source there are a number of ways to create it Either from a base64 string, a buffer, a fetch, or a custom resolve function.