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: mod.rs
    path of file: ./repos/aya/aya/src/sys
    
    the code of the file until where you have to start completion: mod bpf;
mod netlink;
mod perf_event;

#[cfg(test)]
mod fake;

use std::{
    ffi::{c_int, c_long, c_void},
    io, mem,
    os::fd::{AsRawFd as _, BorrowedFd},
};

pub(crate) use bpf::*;
#[cfg(test)]
pub(crate) use fake::*;
use libc::{pid_t, SYS_bpf, SYS_perf_event_open};
#[doc(hidden)]
pub use netlink::netlink_set_link_up;
pub(crate) use netlink::*;
pub(crate) use perf_event::*;
use thiserror::Error;

use crate::generated::{bpf_attr, bpf_cmd, perf_event_attr};

pub(crate) type SysResult<T> = Result<T, (c_long, io::Error)>;

pub(crate) enum Syscall<'a> {
    Ebpf {
        cmd: bpf_cmd,
        attr: &'a mut bpf_attr,
    },
    PerfEventOpen {
        attr: perf_event_attr,
        pid: pid_t,
        cpu: i32,
        group: i32,
        flags: u32,
    },
    PerfEventIoctl {
        fd: BorrowedFd<'a>,
        request: c_int,
        arg: c_int,
    },
}

#[derive(Debug, Error)]
    
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Ebpf { cmd, attr: _ } => f
                .debug_struct("Syscall::Ebpf")
                .field("cmd", cmd)
                .field("attr", &format_args!("_"))
                .finish(),
            Self::PerfEventOpen {
                attr: _,
                pid,
                cpu,
                group,
                flags,
            } => f
                .debug_struct("Syscall::PerfEventOpen")
                .field("attr", &format_args!("_"))
                .field("pid", pid)
                .field("cpu", cpu)
                .field("group", group)
                .field("flags", flags)
                .finish(),
            Self::PerfEventIoctl { fd, request, arg } => f
                .debug_struct("Syscall::PerfEventIoctl")
                .field("fd", fd)
                .field("request", request)
                .field("arg", arg)
                .finish(),
        }
    }