How do I build a rate limiter in Go?

package main

import (
    "fmt"
    "time"
)

type RateLimiter struct {
    tokens      chan struct{}
    requestRate time.Duration
}

func NewRateLimiter(rate int, burst int) *RateLimiter {
    rl := &RateLimiter{
        tokens:      make(chan struct{}, burst),
        requestRate: time.Second / time.Duration(rate),
    }

    // Fill the token bucket
    go func() {
        ticker := time.NewTicker(rl.requestRate)
        defer ticker.Stop()
        for {
            <-ticker.C
            select {
            case rl.tokens <- struct{}{}: // Add a token to the bucket
            default: // Bucket is full, ignore
            }
        }
    }()
    return rl
}

func (rl *RateLimiter) Allow() bool {
    select {
    case <-rl.tokens: // Take a token from the bucket
        return true
    default: // No token available
        return false
    }
}

func main() {
    rl := NewRateLimiter(2, 5) // 2 requests per second, with a burst of 5 requests

    for i := 0; i < 10; i++ {
        if rl.Allow() {
            fmt.Println("Request allowed")
        } else {
            fmt.Println("Request denied")
        }
        time.Sleep(200 * time.Millisecond) // Simulating request interval
    }
}