create a goroutine within router func will report wrote more than declared Content-Length

[little-guy-lxr]

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Description

How to reproduce

package main import ( "github.com/gin-gonic/gin" )

func Response(c gin.Context){ c.String(200, "Hello %s", c.Param("name")) } func main() { g := gin.Default() g.GET("/hello/:name", func(c gin.Context) { go Response(c) }) g.Run(":9000") }

## Expectations

$ curl http://localhost:8201/hello/world
Hello world

## Actual result

<!-- Actual result showing the problem -->

$ curl -i http://localhost:8201/hello/world

server core panic : wrote more than declared Content-Length ## Environment - go version: 1.22.5 - gin version (or commit ref): 094b3fdb393ff8eab16ec293bf49513213955523 - operating system:

[linvis]

Gin doesn't allow use original context in goroutine.

first, original context is not allowed second, context copy is only read-only

see more https://github.com/gin-gonic/gin#goroutines-inside-a-middleware