Gin context duplicated using context.Copy() still points to the original request body

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Description

context.Copy() does not duplicate the request body source. So reading in the copied context closes the stream in the original context as well

How to reproduce

package main

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

func main() {
    g := gin.Default()
    g.POST("/hello", func(c *gin.Context) {
        go func(ccp *gin.Context) {
            _, _ = ioutil.ReadAll(ccp.Request.Body)
        }(c.Copy())
        time.Sleep(50) // Let goroutine read the body
        body, _ := ioutil.ReadAll(c.Request.Body)

        c.String(200, "Hello. I got this request from you: %s", string(body))
    })
    g.Run(":9000")
}

Expectations

$ curl -X POST --location "http://localhost:9000/hello" \
    -H "Content-Type: application/json" \
    -d "{\"test\": \"value\"}"
Hello. I got this request from you: {"test": "value"}

Actual result

$ curl -X POST --location "http://localhost:9000/hello" \
    -H "Content-Type: application/json" \
    -d "{\"test\": \"value\"}"
Hello. I got this request from you: 

Environment

• go version: 1.19
• gin version (or commit ref): v1.6.3
• operating system: Mac

Comment From: timandy

I think the author does not copy the body to save memory, and I agree with the author's design. If you want to pass the content of the body, you should read it first, and then pass the readed result in different coroutines.