pub trait PoolState {
// Required methods
fn get_size(&self) -> usize;
fn get_queue_length(&self) -> usize;
fn get_priority_queue_length(&self) -> usize;
fn get_queue_size_threshold(&self) -> usize;
fn set_queue_size_threshold(&mut self, threshold: usize);
fn get_first_worker_id(&self) -> Option<usize>;
fn get_last_worker_id(&self) -> Option<usize>;
fn get_next_worker_id(&self, id: usize) -> Option<usize>;
}