future3: Speed up sync from local folders and network mounts

[jdeitmerg]

Syncing from my home server felt a bit slow. Wifi is the bottleneck, but an improvement of ~25% could still be attained with this patch.

I ran some tests using (the awesome!) hyperfine, copying a 127MB mp3 from a cifs-mounted samba share to a local folder.

Command (abbreviated)	Mean [s]	Min [s]	Max [s]	Relative
rsync --compress	28.745 ± 1.040	27.546	30.406	1.44 ± 0.06
rsync	23.255 ± 0.298	22.908	23.556	1.16 ± 0.02
cp	19.986 ± 0.322	19.657	20.450	1.00

cp is handsdown fastest. For rsync, --compress incurs the ~25% penalty I mentioned above.

I assume --compress does speed up SSH-transfers, so I left it in for those.

[coveralls]

Pull Request Test Coverage Report for Build 20995868324

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 38.14%

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Totals
Change from base Build 19665970285:	0.0%
Covered Lines:	492
Relevant Lines:	1290

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 20995868345

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 38.14%

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Totals
Change from base Build 19665970285:	0.0%
Covered Lines:	492
Relevant Lines:	1290

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💛 - Coveralls