Pipe

将当前Reader pipe向Response，用于流式输出响应数据，节省内存使用。

Example

package main
import (
    "bytes"
    "github.com/vicanso/elton"
    "github.com/vicanso/elton/middleware"
)
func main() {
    e := elton.New()
    e.Use(middleware.NewDefaultResponder())
    e.GET("/", func(c *elton.Context) (err error) {
        buf := new(bytes.Buffer)
        for i := 0; i < 1000; i++ {
            buf.WriteString("Hello, World!\n")
        }
        _, _ = c.Pipe(buf)
        return
    })
    err := e.ListenAndServe(":3000")
    if err != nil {
        panic(err)
    }
}