func (rb *reorderBuffer) setFlusher(out []byte, f func(*reorderBuffer) bool) {
	rb.out = out
	rb.flushF = f
}

// reset discards all characters from the buffer.
func (rb *reorderBuffer) reset() {
	rb.nrune = 0
	rb.nbyte = 0
}

func (rb *reorderBuffer) doFlush() bool {
	if rb.f.composing {
		rb.compose()
	}
	res := rb.flushF(rb)
	rb.reset()
	return res
}

func (rb *reorderBuffer) setFlusher(out []byte, f func(*reorderBuffer) bool) {
	rb.out = out
	rb.flushF = f
}

// reset discards all characters from the buffer.
func (rb *reorderBuffer) reset() {
	rb.nrune = 0
	rb.nbyte = 0
}

func (rb *reorderBuffer) doFlush() bool {
	if rb.f.composing {
		rb.compose()
	}
	res := rb.flushF(rb)
	rb.reset()
	return res
}

	ft := formTable[f]
	n, ok := ft.quickSpan(src, 0, len(b), true)
	if ok {
		return b
	}
	out := make([]byte, n, len(b))
	copy(out, b[0:n])
	rb := reorderBuffer{f: *ft, src: src, nsrc: len(b), out: out, flushF: appendFlush}
	return doAppendInner(&rb, n)
}

// String returns f(s).
func (f Form) String(s string) string {
	src := inputString(s)
	ft := formTable[f]
	n, ok := ft.quickSpan(src, 0, len(s), true)
	if ok {

	ft := formTable[f]
	n, ok := ft.quickSpan(src, 0, len(b), true)
	if ok {
		return b
	}
	out := make([]byte, n, len(b))
	copy(out, b[0:n])
	rb := reorderBuffer{f: *ft, src: src, nsrc: len(b), out: out, flushF: appendFlush}
	return doAppendInner(&rb, n)
}

// String returns f(s).
func (f Form) String(s string) string {
	src := inputString(s)
	ft := formTable[f]
	n, ok := ft.quickSpan(src, 0, len(s), true)
	if ok {

	}
	// Clear tinyalloc pool.
	c.tiny = 0
	c.tinyoffset = 0

	// Flush tinyAllocs.
	stats := memstats.heapStats.acquire()
	atomic.Xadd64(&stats.tinyAllocCount, int64(c.tinyAllocs))
	c.tinyAllocs = 0
	memstats.heapStats.release()

	// Update heapLive and heapScan.
	gcController.update(dHeapLive, scanAlloc)
}

// prepareForSweep flushes c if the system has entered a new sweep phase

// complete for formatting purposes.
func (b *Writer) Flush() error {
	return b.flush()
}

// flush is the internal version of Flush, with a named return value which we
// don't want to expose.
func (b *Writer) flush() (err error) {
	defer b.handlePanic(&err, "Flush")
	b.flushNoDefers()
	return nil
}

// flushNoDefers is like flush, but without a deferred handlePanic call. This

// If the underlying writer returns an error, Flush returns that error.
//
// In the terminology of the zlib library, Flush is equivalent to Z_SYNC_FLUSH.
func (w *Writer) Flush() error {
	// For more about flushing:
	// https://www.bolet.org/~pornin/deflate-flush.html
	return w.d.syncFlush()
}

// Close flushes and closes the writer.
func (w *Writer) Close() error {
	return w.d.close()
}

	if len(contentType) == 0 {
		contentType = "application/octet-stream"
	}
	w.Header().Set("Content-Type", contentType)
	w.WriteHeader(statusCode)
	// Flush headers, if possible
	if flusher, ok := w.(http.Flusher); ok {
		flusher.Flush()
	}
	writer := w.(io.Writer)
	if flush {
		writer = flushwriter.Wrap(w)
	}
	io.Copy(writer, out)
}

}

func testTrailersServerToClient(t *testing.T, mode testMode, flush bool) {
	const body = "Some body"
	cst := newClientServerTest(t, mode, HandlerFunc(func(w ResponseWriter, r *Request) {
		w.Header().Set("Trailer", "Server-Trailer-A, Server-Trailer-B")
		w.Header().Add("Trailer", "Server-Trailer-C")

		io.WriteString(w, body)
		if flush {
			w.(Flusher).Flush()
		}

		// How handlers set Trailers: declare it ahead of time

	// flush their own buffers in traceThreadDestroy.
	//
	// Snapshotting freem is necessary because Ms can continue to emit events
	// while they're still on that list. Removal from sched.freem is serialized with
	// this snapshot, so either we'll capture an m on sched.freem and race with
	// the removal to flush its buffers (resolved by traceThreadDestroy acquiring