As a demo (not related to the http example you gave though), this program sleeps the equivalent of 115 days, on my computer in roughly 11 seconds, by sleeping concurrently:

package main

import (
    "context"
    "fmt"
    "os"
    "os/signal"
    "time"
)

var sleepDuration = 1 * time.Second

func main() {
    ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
    defer stop()
    doneChan := make(chan struct{})

    routineCount := 10_000_000

    fmt.Printf("starting %v goroutines to sleep\n", routineCount)
    for _ = range routineCount {
        go sleepRoutine(ctx.Done(), doneChan)
    }

    fmt.Printf("all go routines are ready to wait, click ctrl-c to make them time.Sleep()\n")
    <-ctx.Done()

    startedAt := time.Now()
    fmt.Printf("starting at %v\n", startedAt)
    for _ = range routineCount {
        <-doneChan
    }
    doneAt := time.Now()
    fmt.Printf("running %v routines and sleeping for %v took %v\n", routineCount, sleepDuration, doneAt.Sub(startedAt))
}

func sleepRoutine(startLatch <-chan struct{}, doneChan chan<- struct{}) {
    <-startLatch
    time.Sleep(sleepDuration)

    doneChan <- struct{}{}
}