fetch
abstract fun fetchResourceData(resourceUrl: String, onSuccess: (ByteArray) -> Unit, onError: (ColibrioException) -> Unit)
Fetches a resource from the source publication by URL.
If successful, onSuccess is called with the resource data. Otherwise, onError is called.
Fetches a resource from the source publication by URL.
Return
Either ColibrioResult.Success with the resource data, or ColibrioResult.Error containing the error.