You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: collector.rs
    path of file: ./repos/crossbeam/crossbeam-epoch/src
    
    the code of the file until where you have to start completion: /// Epoch-based garbage collector.
///
/// # Examples
///
/// ```
/// use crossbeam_epoch::Collector;
///
/// let collector = Collector::new();
///
/// let handle = collector.register();
/// drop(collector); // `handle` still works after dropping `collector`
///
/// handle.pin().flush();
/// ```
use core::fmt;

use crate::guard::Guard;
use crate::internal::{Global, Local};
use crate::primitive::sync::Arc;

/// An epoch-based garbage collector.
pub struct Collector {
    pub(crate) global: Arc<Global>,
}

unsafe impl Send for Collector {}
unsafe impl Sync for Collector {}

impl Default for Collector {
    #[allow(clippy::arc_with_non_send_sync)] // https:
    
    fn incremental() {
        #[cfg(miri)]
        const COUNT: usize = 500;
        #[cfg(not(miri))]
        const COUNT: usize = 100_000;
        static DESTROYS: AtomicUsize = AtomicUsize::new(0);

        let collector = Collector::new();
        let handle = collector.register();

        unsafe {
            let guard = &handle.pin();
            for _ in 0..COUNT {
                let a = Owned::new(7i32).into_shared(guard);
                guard.defer_unchecked(move || {
                    drop(a.into_owned());
                    DESTROYS.fetch_add(1, Ordering::Relaxed);
                });
            }
            guard.flush();
        }

        let mut last = 0;

        while last < COUNT {
            let curr = DESTROYS.load(Ordering::Relaxed);
            assert!(curr - last <= 1024);
            last = curr;

            let guard = &handle.pin();
            collector.global.collect(guard);
        }
        assert!(DESTROYS.load(Ordering::Relaxed) == COUNT);
    }