instead of skipping, let's prepare the parts and mark it noop

[TingDaoK]

• Refactoring the resume logic to instead of skipping parts during preparing other parts, we prepare those parts already uploaded, and then make it noop. After we read the part, we check the checksum and length.

TODO:

Maybe, we can be more smarter? If the part uploaded doesn't have a checksum, we can skip reading the part? Or let user config that if they want us to read the parts uploaded.

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