resume download

[hopeyen]

Description

A user can optionally provide a file path to store download progress in case of failure and early cut-off. The progress is stored in a json file, in which an inner option is the map of file manifest ipfs hash to the missing chunk indices.
Progress gets stored when a file ran out of maximum attempt and there's no available indexers, or when user presses ctrl+c.
With this file, the downloader can continue downloading from a previous session.

Issue link (if applicable)

Resolves #32

Checklist

• Are tests up-to-date with the new changes?
• Are docs up-to-date with the new changes? (Open PR on docs repo if necessary)

[github-actions]

Pull Request Test Coverage Report for Build 8444024390

Details

• 0 of 94 (0.0%) changed or added relevant lines in 3 files are covered.
• 5 unchanged lines in 1 file lost coverage.
• Overall coverage remained the same at 0.0%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
file-exchange/src/main.rs	0	13	0.0%
file-exchange/src/util.rs	0	28	0.0%
file-exchange/src/download_client/mod.rs	0	53	0.0%

Files with Coverage Reduction	New Missed Lines	%
file-exchange/src/download_client/mod.rs	5	0.0%

Totals
Change from base Build 8420566847:	0.0%
Covered Lines:	0
Relevant Lines:	3720

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💛 - Coveralls