Struct TokenBucket 

pub struct TokenBucket {
    tokens: f64,
    capacity: f64,
    refill_rate: f64,
    last_refill: Instant,
}

Token-bucket rate limiter. Stores the bucket state; wrap in Arc<RwLock<_>> to share across concurrent download tasks.

Fields

tokens: f64

Available tokens (bytes).

capacity: f64

Burst capacity (bytes).

refill_rate: f64

Bytes-per-second refill rate.

last_refill: Instant

Monotonic timestamp of the last refill.

Implementations

impl TokenBucket

pub fn new(bytes_per_sec: u64, capacity_factor: f64) -> Self

Create a bucket with bytes_per_sec sustained throughput and a burst buffer of capacity_factor seconds’ worth of tokens.

pub fn refill(&mut self)

Replenish tokens based on elapsed wall time. Call before every consume.

pub fn try_consume(&mut self, bytes: u64) -> u64

Consume up to bytes tokens immediately. Returns how many were consumed. Does not block - the caller decides what to do with remaining deficit.

pub async fn consume(&mut self, bytes: u64) -> Result<()>

Async-wait until bytes tokens are available, then consume them. Polls at most every 100 ms so Tokio’s timer wheel stays responsive.

pub fn set_rate(&mut self, bytes_per_sec: u64)

Adjust the sustained rate. Burst capacity is reset to 5× the new rate.

Trait Implementations

impl Debug for TokenBucket

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.