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: interfaces.rs
    path of file: ./repos/redshirt/kernel/core/src/system
    
    the code of the file until where you have to start completion: // Copyright (C) 2019-2021  Pierre Krieger
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU 
    
    pub fn new() -> Self {
        Interfaces {
            inner: spinning_top::Spinlock::new(Inner {
                interfaces: Default::default(),
                registrations: {
                    // Registration IDs are of the type `NonZeroU64`.
                    // The list of registrations starts with an entry at index `0` in order for
                    // generated registration IDs to never be equal to 0.
                    let mut registrations = slab::Slab::default();
                    let _id = registrations.insert(InterfaceRegistration {
                        interface: InterfaceHash::from_raw_hash(Default::default()),
                        pid: 0xdeadbeef.into(), // TODO: ?!
                        queries: VecDeque::new(),
                        pending_accept: VecDeque::new(),
                    });
                    assert_eq!(_id, 0);
                    registrations
                },
            }),
        }
    }