It does diff, and can be configured to use various diff methods (checksum, modified datetime). I use it with S3 and to diff with checksum it needs to do an expe

It does diff, and can be configured to use various diff methods (checksum, modified datetime). I use it with S3 and to diff with checksum it needs to do an expensive, slow metadata read - so I use `--use-server-modtime` which only copies files newer than the remote S3 file time. https://rclone.org/s3/ https://rclone.org/s3/