fix(context): data race

[0xff-dev]

Pull Request Checklist

fix(context): data race

package main

import (
	"sync"

	"github.com/gin-gonic/gin"
)

func main() {
	e := gin.Default()
	e.GET("/hello", func(ctx *gin.Context) {
		var wg sync.WaitGroup
		const n = 20

		wg.Add(1)
		go func() {
			defer wg.Done()
			for i := 0; i < n; i++ {
				ctx.Set("key", i)
			}
		}()
		wg.Add(1)
		go func() {
			defer wg.Done()
			for i := 0; i < n; i++ {
				_ = ctx.Copy()
			}
		}()
		wg.Wait()
		_, _ = ctx.Writer.Write([]byte("done"))
	})

	e.Run(":8098")
}

run

go run -race main.go

test

curl http://127.0.0.1:8098/hello

outout

==================
WARNING: DATA RACE
Write at 0x00c0001fc280 by goroutine 10:

Please ensure your pull request meets the following requirements:

• Open your pull request against the master branch.
• All tests pass in available continuous integration systems (e.g., GitHub Actions).
• Tests are added or modified as needed to cover code changes.
• If the pull request introduces a new feature, the feature is documented in the docs/doc.md.

Thank you for contributing!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.37%. Comparing base (3dc1cd6) to head (34ff4d8).
⚠️ Report is 276 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4660      +/-   ##
==========================================
- Coverage   99.21%   98.37%   -0.85%     
==========================================
  Files          42       48       +6     
  Lines        3182     3137      -45     
==========================================
- Hits         3157     3086      -71     
- Misses         17       42      +25     
- Partials        8        9       +1     

Flag	Coverage Δ
	?
--ldflags="-checklinkname=0" -tags sonic	98.36% <100.00%> (?)
-tags go_json	98.29% <100.00%> (?)
-tags nomsgpack	98.35% <100.00%> (?)
go-1.18	?
go-1.19	?
go-1.20	?
go-1.21	?
go-1.25	98.37% <100.00%> (?)
go-1.26	98.37% <100.00%> (?)
macos-latest	98.37% <100.00%> (-0.85%)	⬇️
ubuntu-latest	98.37% <100.00%> (-0.85%)	⬇️

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