source: code/trunk/vendor/github.com/valyala/fasthttp/stream.go@ 145

package fasthttp

import (
        "bufio"
        "io"
        "sync"

        "github.com/valyala/fasthttp/fasthttputil"
)

// StreamWriter must write data to w.
//
// Usually StreamWriter writes data to w in a loop (aka 'data streaming').
//
// StreamWriter must return immediately if w returns error.
//
// Since the written data is buffered, do not forget calling w.Flush
// when the data must be propagated to reader.
type StreamWriter func(w *bufio.Writer)

// NewStreamReader returns a reader, which replays all the data generated by sw.
//
// The returned reader may be passed to Response.SetBodyStream.
//
// Close must be called on the returned reader after all the required data
// has been read. Otherwise goroutine leak may occur.
//
// See also Response.SetBodyStreamWriter.
func NewStreamReader(sw StreamWriter) io.ReadCloser {
        pc := fasthttputil.NewPipeConns()
        pw := pc.Conn1()
        pr := pc.Conn2()

        var bw *bufio.Writer
        v := streamWriterBufPool.Get()
        if v == nil {
                bw = bufio.NewWriter(pw)
        } else {
                bw = v.(*bufio.Writer)
                bw.Reset(pw)
        }

        go func() {
                sw(bw)
                bw.Flush()
                pw.Close()

                streamWriterBufPool.Put(bw)
        }()

        return pr
}

var streamWriterBufPool sync.Pool