Function retry_with_backoff 

pub async fn retry_with_backoff<F, Fut, T>(
    op: F,
    max_retries: usize,
    initial_delay: Duration,
    context: &str,
) -> Result<T>
where
    F: FnMut() -> Fut,
    Fut: Future<Output = Result<T>>,

Retry an operation with exponential backoff