Struct TokenBucketLimiter 

pub struct TokenBucketLimiter { /* private fields */ }

Caps the number of starts allowed per refill window (token-bucket algorithm).

capacity tokens are available at startup; a background task adds one token every 1 / refill_per_sec seconds, up to capacity. acquire() waits for a token and consumes it (the refiller restores tokens over time).

Panics (constructor)

new asserts capacity > 0 and refill_per_sec > 0.0. These are API misuse guards: a zero capacity would permanently block all callers and a non-positive rate is mathematically undefined, so a panic at construction time is the right signal.

Refiller lifecycle

The background refiller task self-terminates one tick after the limiter is dropped (Arc::strong_count == 1). This avoids leaking a task per limiter. If a stricter shutdown is needed later, store a tokio::task::JoinHandle

• Notify and abort on Drop; not required for the initial implementation.

Implementations

impl TokenBucketLimiter

pub fn new(capacity: usize, refill_per_sec: f64) -> TokenBucketLimiter

Create a new token-bucket limiter.

• capacity — maximum burst size (initial token count, upper refill bound).
• refill_per_sec — tokens restored per second.

Panics

Panics if capacity == 0 or refill_per_sec <= 0.0 (API misuse guards).

Trait Implementations

impl RateLimiter for TokenBucketLimiter

fn acquire<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>

where 'life0: 'async_trait, TokenBucketLimiter: 'async_trait,

Wait until the caller is permitted to start an external call.