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Synapse will assume their role (with ExternalId=their user id) and create a pre-signed URL to download the file. Egress costs go to the data downloader's AWS accounaccount.t
Pros:
Simplicity: The downloaded file is not copied. There is no extra file handle or file entity created. All Synapse features for data download can be used.
Cons:
Access control: Upon set up the collaborator has access to the entire bucket in S3. Synapse's sharing settings and governance controls will limit creation of presigned URLs but will not limit the data accessor's ability to access the bucket through S3.
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