Use IndexAny instead of Split to reduce memory allocation

[imxyb]

benchcmp result:

benchcmp is deprecated in favor of benchstat: https://pkg.go.dev/golang.org/x/perf/cmd/benchstat
benchmark                                  old ns/op     new ns/op     delta
BenchmarkRealIPForHeaderXForwardFor-12     128           39.7          -68.98%

before:

goos: darwin
goarch: amd64
pkg: github.com/labstack/echo/v4
BenchmarkRealIP-12       8774244               130 ns/op              48 B/op          1 allocs/op
PASS
ok      github.com/labstack/echo/v4     1.297s

after:

goos: darwin
goarch: amd64
pkg: github.com/labstack/echo/v4
BenchmarkRealIP-12      28132903                38.2 ns/op             0 B/op          0 allocs/op
PASS
ok      github.com/labstack/echo/v4     1.133s

[codecov]

Codecov Report

Merging #1640 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1640      +/-   ##
==========================================
+ Coverage   85.28%   85.30%   +0.01%     
==========================================
  Files          28       28              
  Lines        2216     2219       +3     
==========================================
+ Hits         1890     1893       +3     
  Misses        212      212              
  Partials      114      114              

Impacted Files	Coverage Δ
context.go	89.84% <100.00%> (+0.12%)	⬆️

---

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[lammel]

The title says IndexByte but in the code string.IndexAny() is used.
IndexByte cam with Go 1.2 so that is also fine. Tests should be adjusted to cover the missing cases (as code coverage dropped)

What was used in the benchmarks actually?

[imxyb]

The title says IndexByte but in the code string.IndexAny() is used.
IndexByte cam with Go 1.2 so that is also fine. Tests should be adjusted to cover the missing cases (as code coverage dropped)

What was used in the benchmarks actually?

sorry, the title is incorrect, I have changed it back and use IndexAny correctly.I will improve the test coverage later

[imxyb]

@lammel PTAL

[lammel]

Nice! Will take a look later on.

[imxyb]

hi，any update? @lammel

[lammel]

Tested for benchmark regressions on the PR branch.

PR branch feature/opt-split:

sh# /usr/bin/go test -benchmem -run=^$ github.com/labstack/echo/v4 -bench ^Benchmark -benchtime 5s
goos: linux
goarch: amd64
pkg: github.com/labstack/echo/v4
BenchmarkBindbindData-8                 	  773809	      8006 ns/op	     368 B/op	      40 allocs/op
BenchmarkBindbindDataWithTags-8         	  600234	      9815 ns/op	     408 B/op	      39 allocs/op
BenchmarkAllocJSONP-8                   	16191808	       369 ns/op	     155 B/op	       4 allocs/op
BenchmarkAllocJSON-8                    	24182094	       240 ns/op	      95 B/op	       1 allocs/op
BenchmarkAllocXML-8                     	 4307667	      1398 ns/op	    4751 B/op	      10 allocs/op
BenchmarkRealIPForHeaderXForwardFor-8   	152748471	        38.7 ns/op	       0 B/op	       0 allocs/op
BenchmarkContext_Store-8                	133940372	        44.3 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterStaticRoutes-8           	  484891	     12681 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterGitHubAPI-8              	  249950	     23171 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterParseAPI-8               	 1406133	      4247 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterGooglePlusAPI-8          	  884396	      6860 ns/op	       0 B/op	       0 allocs/op
PASS
ok  	github.com/labstack/echo/v4	81.256s

compared to current master:

 /usr/bin/go test -benchmem -run=^$ github.com/labstack/echo/v4 -bench ^Benchmark -benchtime 5s
goos: linux
goarch: amd64
pkg: github.com/labstack/echo/v4
BenchmarkBindbindData-8                 	  763737	      8278 ns/op	     368 B/op	      40 allocs/op
BenchmarkBindbindDataWithTags-8         	  599168	      9928 ns/op	     408 B/op	      39 allocs/op
BenchmarkAllocJSONP-8                   	16310584	       377 ns/op	     154 B/op	       4 allocs/op
BenchmarkAllocJSON-8                    	24018079	       244 ns/op	      95 B/op	       1 allocs/op
BenchmarkAllocXML-8                     	 4306189	      1411 ns/op	    4751 B/op	      10 allocs/op
BenchmarkRealIPForHeaderXForwardFor-8   	49710991	       114 ns/op	      48 B/op	       1 allocs/op
BenchmarkContext_Store-8                	132688436	        47.3 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterStaticRoutes-8           	  539204	     11651 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterGitHubAPI-8              	  259131	     23709 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterParseAPI-8               	 1487281	      4015 ns/op	       0 B/op	       0 allocs/op
BenchmarkRouterGooglePlusAPI-8          	  919380	      6719 ns/op	       0 B/op	       0 allocs/op
PASS
ok  	github.com/labstack/echo/v4	78.373s

No regressions seen. PR looks OK.
Thanks a lot @imxyb . Merged.