The bytes of the base64 encoded asset bundle import zip file. This file can't exceed 20 MB. If the size of the file that you want to upload is more than 20 MB, add the file to your Amazon S3 bucket and use S3Uri of the file for this operation.
The Amazon S3 URI for an asset bundle import file that exists in an Amazon S3 bucket that the caller has read access to. The file must be a zip format file and can't exceed 1 GB.