Make all download functions need only Config, not Builder

[jyn514]

This also adds a new mod download instead of scattering the download code across config.rs and native.rs.

This is the simplest and also most bit-rotty part of #102282. Opening it earlier so it's not mixed in with behavior changes and to avoid rebase hell.

cc #94829 (which nows has the hackmd linked).

r? @Mark-Simulacrum

[jyn514]

@bors p=5 prone to bitrot

[jyn514]

In retrospect I probably should have separated the move to a different file into its own commit :( let me know if you want me to spend time on that.

[bors]

☔ The latest upstream changes (presumably #104078) made this pull request unmergeable. Please resolve the merge conflicts.

[Mark-Simulacrum]

Apologies for a slower review here -- r=me on this with a rebase.

[jyn514]

Thanks!

@bors r=Mark-Simulacrum rollup=iffy

[bors]

📌 Commit fb471de has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[bors]

⌛ Testing commit fb471de with merge f90a4ff...

[bors]

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing f90a4ff to master...

[rust-timer]

Finished benchmarking commit (f90a4ff): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.7%	[-5.1%, -2.9%]	4
All ❌✅ (primary)	-	-	0

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.5%	[-5.8%, -3.2%]	6
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-4.5%	[-5.8%, -3.2%]	6