**FastAPI** hoàn toàn được dựa trên những gợi ý kiểu dữ liệu, chúng mang đến nhiều ưu điểm và lợi ích.

Nhưng thậm chí nếu bạn không bao giờ sử dụng **FastAPI**, bạn sẽ được lợi từ việc học một ít về chúng.

!!! note
    Nếu bạn là một chuyên gia về Python, và bạn đã biết mọi thứ về gợi ý kiểu dữ liệu, bỏ qua và đi tới chương tiếp theo.

## Động lực

Hãy bắt đầu với một ví dụ đơn giản:

	//   (c) If there's nothing left to advance, goto (1).
	// (6) Select the latest event for the selected M and get it ready to be returned.
	// (7) Read the next event for the selected M and update the min-heap.
	// (8) Return the selected event, goto (5) on the next call.

	// Set us up to track the last timestamp and fix up
	// the timestamp of any event that comes through.

	globalMetricGenerator
	stackSampleGenerator[trace.GoID]
	logEventGenerator[trace.GoID]

	gStates map[trace.GoID]*gState[trace.GoID]
	focus   trace.GoID
	filter  map[trace.GoID]struct{}
}

func newGoroutineGenerator(ctx *traceContext, focus trace.GoID, filter map[trace.GoID]struct{}) *goroutineGenerator {
	gg := new(goroutineGenerator)
	rg := func(ev *trace.Event) trace.GoID {
		return ev.Goroutine()
	}

	}

	// Test the function.
	targetg := trace.GoID(86)
	got := trace.RelatedGoroutinesV2(events, targetg)
	want := map[trace.GoID]struct{}{
		trace.GoID(86):  struct{}{}, // N.B. Result includes target.
		trace.GoID(71):  struct{}{},
		trace.GoID(25):  struct{}{},
		trace.GoID(122): struct{}{},
	}
	for goid := range got {
		if _, ok := want[goid]; ok {
			delete(want, goid)
		} else {

		continue L1 /* ERROR "invalid continue label L1" */
		continue L2 /* ERROR "invalid continue label L2" */
		continue L3
		goto L1
		goto L2
		goto L3
	}
}

// Blank labels are never declared.

func f4() {
_:
_: // multiple blank labels are ok
	goto _ /* ERROR "label _ not declared" */
}

func f5() {
_:
	for {
		break _ /* ERROR "invalid break label _" */

		if err1 != 0 {
			goto childerror
		}
		if pid != unsafe.Sizeof(err2) {
			err1 = EINVAL
			goto childerror
		}
		if err2 != 0 {
			err1 = err2
			goto childerror
		}
	}

	// Session ID
	if sys.Setsid {
		_, _, err1 = RawSyscall(SYS_SETSID, 0, 0, 0)
		if err1 != 0 {
			goto childerror
		}
	}

	// Set process group
	if sys.Setpgid || sys.Foreground {

		}
		if goids := r.FormValue("goid"); goids != "" {
			// Render trace focused on a particular goroutine.

			id, err := strconv.ParseUint(goids, 10, 64)
			if err != nil {
				log.Printf("failed to parse goid parameter %q: %v", goids, err)
				return
			}
			goid := trace.GoID(id)
			g, ok := parsed.summary.Goroutines[goid]
			if !ok {
				log.Printf("failed to find goroutine %d", goid)

package config

import (
	"bytes"
	"encoding/json"
	"fmt"
	"reflect"
	"time"

	gogojsonpb "github.com/gogo/protobuf/jsonpb" // nolint: depguard
	gogoproto "github.com/gogo/protobuf/proto"   // nolint: depguard
	gogotypes "github.com/gogo/protobuf/types"   // nolint: depguard
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/reflect/protoreflect"

set DEFAULT_JVM_OPTS=-Dfile.encoding=UTF-8 "-Xmx64m" "-Xms64m"

@rem Find java.exe
if defined JAVA_HOME goto findJavaFromJavaHome

set JAVA_EXE=java.exe
%JAVA_EXE% -version >NUL 2>&1
if %ERRORLEVEL% equ 0 goto execute

echo. 1>&2
echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
echo. 1>&2

		Tasks:      s.tasks,
	}
}

// RelatedGoroutinesV2 finds a set of goroutines related to goroutine goid for v2 traces.
// The association is based on whether they have synchronized with each other in the Go
// scheduler (one has unblocked another).
func RelatedGoroutinesV2(events []Event, goid GoID) map[GoID]struct{} {
	// Process all the events, looking for transitions of goroutines