Specialize many implementations of Read::read_buf_exact

[a1phyr]

This makes all implementations of Read that have a specialized read_exact implementation also have one for read_buf_exact.

[rustbot]

r? @m-ou-se

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[joboet]

Cool, thank you!
@bors r+

[bors]

📌 Commit 8734809 has been approved by joboet

It is now in the queue for this repository.

[bors]

⌛ Testing commit 8734809 with merge e908cfd...

[bors]

☀️ Test successful - checks-actions
Approved by: joboet
Pushing e908cfd to master...

[rust-timer]

Finished benchmarking commit (e908cfd): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.3%, -0.3%]	1
Improvements ✅ (secondary)	-1.6%	[-1.6%, -1.6%]	1
All ❌✅ (primary)	-0.3%	[-0.3%, -0.3%]	1

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)	-4.1%	[-6.1%, -2.9%]	3
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-4.1%	[-6.1%, -2.9%]	3

Cycles

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

Binary size

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)	0.0%	[0.0%, 0.0%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.4%, -0.2%]	6
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.2%	[-0.4%, 0.0%]	9

Bootstrap: 674.485s -> 672.464s (-0.30%)
Artifact size: 318.39 MiB -> 318.41 MiB (0.01%)