The S3 URI of the media file to send, in the format s3://bucket-name/key. The service downloads the file from your S3 bucket, rehosts it, and generates a presigned URL for the aggregator. Maximum 2000 characters.
s3://bucket-name/key
The S3 URI of an optional thumbnail image for the media file, in the format s3://bucket-name/key. Maximum 2000 characters.