Golang "Canceling" (Useless without something like net.Context)

test.go

package main

import (
        "fmt"
        "time"
)

func main() {
        c := make(chan string, 1)
        go func() { c <- mysleep() }()
        select {
        case <-c:
                fmt.Println("returned")
        case <-time.After(time.Second * 1):
                fmt.Println("timeout")
        }
        time.Sleep(time.Second * 20)
}

func mysleep() string {
        defer fmt.Println("defer")
        fmt.Println("enter")
        time.Sleep(time.Second * 20)
        defer fmt.Println("exit")
        return "return"
}

trace.log

17:37:40 $ go run /tmp/test.go
enter
timeout
SIGQUIT: quit
PC=0x459213 m=0

goroutine 6 [syscall]:
runtime.notetsleepg(0x58b798, 0x46c75ab6f, 0x0)
        /usr/local/go/src/runtime/lock_futex.go:205 +0x4e fp=0xc820028738 sp=0xc820028710
runtime.timerproc()
        /usr/local/go/src/runtime/time.go:209 +0xde fp=0xc8200287c0 sp=0xc820028738
runtime.goexit()
        /usr/local/go/src/runtime/asm_amd64.s:1998 +0x1 fp=0xc8200287c8 sp=0xc8200287c0
created by runtime.addtimerLocked
        /usr/local/go/src/runtime/time.go:116 +0x11f

goroutine 1 [sleep]:
time.Sleep(0x4a817c800)
        /usr/local/go/src/runtime/time.go:59 +0xf9
main.main()
        /tmp/test.go:17 +0x1d0

goroutine 5 [sleep]:
time.Sleep(0x4a817c800)
        /usr/local/go/src/runtime/time.go:59 +0xf9
main.mysleep(0x0, 0x0)
        /tmp/test.go:23 +0x20f
main.main.func1(0xc82006c060)
        /tmp/test.go:10 +0x18
created by main.main
        /tmp/test.go:10 +0x74

rax    0xfffffffffffffffc
rbx    0xc8200286c8
rcx    0xffffffffffffffff
rdx    0x0
rdi    0x58b798
rsi    0x0
rbp    0x3b93776f
rsp    0xc820028690
r8     0x0
r9     0x0
r10    0xc8200286c8
r11    0x206
r12    0x1
r13    0x52ef52
r14    0x9
r15    0x8
rip    0x459213
rflags 0x206
cs     0x33
fs     0x0
gs     0x0
exit status 2
17:37:44 $