Function retry 

pub async fn retry<F, Fut, T, E>(policy: &RetryPolicy, f: F) -> Result<T, E>
where
    F: FnMut() -> Fut,
    Fut: Future<Output = Result<T, E>>,

Execute an async operation with automatic retry according to a RetryPolicy.

Returns the first Ok value, or the last Err after all attempts are exhausted. Each retry sleeps for an exponentially increasing delay with jitter.

Example

use stygian_graph::adapters::resilience::{RetryPolicy, retry};
use std::sync::atomic::{AtomicU32, Ordering};
use std::sync::Arc;
use std::time::Duration;

let attempts = Arc::new(AtomicU32::new(0));
let policy = RetryPolicy::new(3, Duration::from_millis(1), Duration::from_millis(10))
    .with_jitter_ms(0);

let result = retry(&policy, || {
    let counter = Arc::clone(&attempts);
    async move {
        let n = counter.fetch_add(1, Ordering::SeqCst);
        if n < 2 { Err("not yet".to_string()) } else { Ok(n) }
    }
}).await;

assert!(result.is_ok());
assert_eq!(attempts.load(Ordering::SeqCst), 3);