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: eventedfd.rs
    path of file: ./repos/rio/corcovado/src/sys/fuchsia
    
    the code of the file until where you have to start completion: use libc;
use std::mem;
use std::os::unix::io::RawFd;
use std::sync::{Arc, Mutex};
use sys::fuchsia::{poll_opts_to_wait_async, sys, DontDrop};
use zircon;
use zircon::AsHandleRef;
use
    
    pub fn rereg_for_level(&self, port: &zircon::Port) {
        let registration_opt = self.registration.lock().unwrap();
        if let Some(ref registration) = *registration_opt {
            if let Some((rereg_signals, rereg_opts)) = registration.rereg_signals {
                let _res = registration.handle.inner_ref().wait_async_handle(
                    port,
                    registration.token.0 as u64,
                    rereg_signals,
                    rereg_opts,
                );
            }
        }
    }