}

	// Check with width cap
	if bp.WidthCap() != capWidth {
		t.Fatalf("bytepool capWidth invalid: got %v want %v", bp.WidthCap(), capWidth)
	}

	// Check that retrieved buffer are of the expected width
	b := bp.Get()
	if len(b) != width {
		t.Fatalf("bytepool length invalid: got %v want %v", len(b), width)
	}
	if cap(b) != capWidth {
		t.Fatalf("bytepool cap invalid: got %v want %v", cap(b), capWidth)
	}

func (s *scratch) grow() {
	ndata := make([]byte, cap(s.data)*2)
	copy(ndata, s.data)
	s.data = ndata
}

// append single byte to scratch buffer
func (s *scratch) add(c byte) {
	if s.fill+1 >= cap(s.data) {
		s.grow()
	}

	s.data[s.fill] = c
	s.fill++
}

// append encoded rune to scratch buffer
func (s *scratch) addRune(r rune) int {
	if s.fill+utf8.UTFMax >= cap(s.data) {
		s.grow()
	}

### Tài liệu API thay thế

Và bây giờ, hãy truy cập tới <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>.

Bạn sẽ thấy tài liệu được thay thế (cung cấp bởi <a href="https://github.com/Rebilly/ReDoc" class="external-link" target="_blank">ReDoc</a>):

![ReDoc](https://fastapi.tiangolo.com/img/index/index-02-redoc-simple.png)

## Nâng cấp ví dụ

		w:    width,
		wcap: capwidth,
	}
}

// Populate - populates and pre-warms the byte pool, this function is non-blocking.
func (bp *BytePoolCap) Populate() {
	for _, buf := range reedsolomon.AllocAligned(cap(bp.c), bp.wcap) {
		bp.Put(buf[:bp.w])
	}
}

// Get gets a []byte from the BytePool, or creates a new one if none are
// available in the pool.
func (bp *BytePoolCap) Get() (b []byte) {
	if bp == nil {

	var cap0 int
	for i := 0; i < 5<<10; i++ {
		b.Write(buf)
		b.Read(buf)
		if i == 0 {
			cap0 = b.Cap()
		}
	}
	cap1 := b.Cap()
	// (*Buffer).grow allows for 2x capacity slop before sliding,
	// so set our error threshold at 3x.
	if cap1 > cap0*3 {
		t.Errorf("buffer cap = %d; too big (grew from %d)", cap1, cap0)
	}
}

func BenchmarkWriteByte(b *testing.B) {
	const n = 4 << 10

{"message": "Hello World"}
```

### Tài liệu tương tác API

Bây giờ tới <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

Bạn sẽ thấy một tài liệu tương tác API (cung cấp bởi <a href="https://github.com/swagger-api/swagger-ui" class="external-link" target="_blank">Swagger UI</a>):

![Swagger UI](https://fastapi.tiangolo.com/img/index/index-01-swagger-ui-simple.png)

func (b *Buffer) Len() int { return len(b.buf) - b.off }

// Cap returns the capacity of the buffer's underlying byte slice, that is, the
// total space allocated for the buffer's data.
func (b *Buffer) Cap() int { return cap(b.buf) }

// Available returns how many bytes are unused in the buffer.
func (b *Buffer) Available() int { return cap(b.buf) - len(b.buf) }

		}

		if tc, ok := r.Context().Value(mcontext.ContextTraceKey).(*mcontext.TraceCtxt); ok {
			tc.FuncName = "s3.MaxClients"
		}

		w.Header().Set("X-RateLimit-Limit", strconv.Itoa(cap(pool)))
		w.Header().Set("X-RateLimit-Remaining", strconv.Itoa(cap(pool)-len(pool)))

		ctx := r.Context()
		select {
		case pool <- struct{}{}:
			defer func() { <-pool }()
			globalHTTPStats.addRequestsInQueue(-1)

				return
			}
		case "EcDist":
			var zb0003 uint32
			zb0003, err = dc.ReadArrayHeader()
			if err != nil {
				err = msgp.WrapError(err, "ErasureDist")
				return
			}
			if cap(z.ErasureDist) >= int(zb0003) {
				z.ErasureDist = (z.ErasureDist)[:zb0003]
			} else {
				z.ErasureDist = make([]uint8, zb0003)
			}
			for za0003 := range z.ErasureDist {

		// from this main worker routine will exit
		// once the channel drops below half capacity
		// and when it's been at least 30 seconds since
		// we launched a new worker.
		if mainWorker && len(h.logCh) > cap(h.logCh)/2 {
			nWorkers := h.workers.Load()
			if nWorkers < h.maxWorkers {
				if time.Since(h.lastStarted).Milliseconds() > 10 {
					h.lastStarted = time.Now()
					go h.startQueueProcessor(ctx, false)
				}