A goroutine is a lightweight thread managed by the Go runtime. You start it with the `go` keyword.

• Run tasks concurrently: I/O, API calls, background jobs.
• Improve server throughput by doing work in parallel.

package main
 
import (
    "fmt"
    "time"
)
 
func work(name string) {
    fmt.Println("start:", name)
    time.Sleep(200 * time.Millisecond)
    fmt.Println("done:", name)
}
 
func main() {
    go work("A")
    go work("B")
    time.Sleep(500 * time.Millisecond) // demo: wait a bit
}

• Goroutines may stop when `main` exits.
• In real code, use `sync.WaitGroup` or `context` to control lifecycle.

• lightweight /ˈlaɪtweɪt/: nhẹ, ít tài nguyên
• thread /θred/: luồng
• runtime /ˈrʌntaɪm/: môi trường chạy
• concurrently /kənˈkɝːəntli/: đồng thời
• throughput /ˈθruːpʊt/: thông lượng
• lifecycle /ˈlaɪfˌsaɪkəl/: vòng đời