fix: Decompress request body when multi Content-Encoding sent on request headers

[Jictyvoo]

Description

Currently the Ctx.Body() implementation doesn't parse multi content-encoding body, so in order to attend RFC9110, the Body method was changed, and a new wrapper method to body raw was made.

Fixes #2085

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist:

• For new functionalities I follow the inspiration of the express js framework and built them similar in usage
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation - /docs/ directory for https://docs.gofiber.io/
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• If new dependencies exist, I have checked that they are really necessary and agreed with the maintainers/community (we want to have as few dependencies as possible)
• I tried to make my code as fast as possible with as few allocations as possible
• For new code I have written benchmarks so that they can be analyzed and improved

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[gaby]

@Jictyvoo Thank you for the PR, can you take a look at all the issues raised by golangci-lint. GoFiber currently supports go 1.17-1.20 and some of the functions added in the unit-test are only available in 1.20

[Jictyvoo]

@gaby Oh, I see, I forgot about this lint rules. Already applied all changes needed to pass in the linter. Also, for the errors.Join function, I replaced it to run on previous Go versions as well.

Thanks for the tip

[gaby]

LGTM, although this probably requires updating the version given there's quite a lot changing in Body()

[efectn]

@Jictyvoo can you also update docs, i forgot mentioning it

[ReneWerner87]

@Jictyvoo can you share the times of the benchmark for before and after

[Jictyvoo]

@Jictyvoo can you share the times of the benchmark for before and after

Done some benchmarks using the same test methods on both sources, to ensure that it will not affect the benchmark itself.

Before the change:

goos: linux
goarch: amd64
pkg: github.com/gofiber/fiber/v2
cpu: AMD Ryzen 7 5800X 8-Core Processor             
Benchmark_Ctx_Body_With_Compression
Benchmark_Ctx_Body_With_Compression/gzip
Benchmark_Ctx_Body_With_Compression/gzip-16         	 1882047	       658.6 ns/op	     145 B/op	       7 allocs/op
Benchmark_Ctx_Body_With_Compression/deflate
Benchmark_Ctx_Body_With_Compression/deflate-16      	 2226450	       497.1 ns/op	     129 B/op	       4 allocs/op
Benchmark_Ctx_Body
Benchmark_Ctx_Body-16    	100000000	        13.36 ns/op	       0 B/op	       0 allocs/op
PASS

After the Change:

goos: linux
goarch: amd64
pkg: github.com/gofiber/fiber/v2
cpu: AMD Ryzen 7 5800X 8-Core Processor             
Benchmark_Ctx_Body_With_Compression
Benchmark_Ctx_Body_With_Compression/gzip
Benchmark_Ctx_Body_With_Compression/gzip-16         	 1445175	       728.0 ns/op	     145 B/op	       7 allocs/op
Benchmark_Ctx_Body_With_Compression/gzip,invalid
Benchmark_Ctx_Body_With_Compression/gzip,invalid-16 	 1521243	       806.5 ns/op	     194 B/op	       8 allocs/op
Benchmark_Ctx_Body_With_Compression/deflate
Benchmark_Ctx_Body_With_Compression/deflate-16      	 1965168	       591.5 ns/op	     129 B/op	       4 allocs/op
Benchmark_Ctx_Body_With_Compression/gzip,deflate
Benchmark_Ctx_Body_With_Compression/gzip,deflate-16 	  663676	      1508 ns/op	     377 B/op	      12 allocs/op
Benchmark_Ctx_Body
Benchmark_Ctx_Body-16    	89043600	        13.13 ns/op	       0 B/op	       0 allocs/op
PASS

[ReneWerner87]

thx, looks almost the same -> no performance lose

[Jictyvoo]

@Jictyvoo can you also update docs, i forgot mentioning it

Have updated some, I don't know if it has others than docs/api/ctx.md

[Jictyvoo]

This failed test, I don't see as something that I change, any of you know something about it?

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