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: unix.rs
    path of file: ./repos/lucet/lucet-runtime/lucet-runtime-internals/src/sysdeps
    
    the code of the file until where you have to start completion: use nix::unistd::{sysconf, SysconfVar};
use std::sync::Once;

pub const HOST_PAGE_SIZE_EXPECTED: usize = 4096;
static mut HOST_PAGE_SIZE: usize = 0;
static HOST_PAGE_SIZE_INIT: Once = Once::new();

/// Linux x86-64 and Mac x86-64 hosts should always use a 4K page.
///
/// We double check the expected value using `sysconf` at runtime.
pub fn host_page_size() -> usize {
    unsafe {
        HOST_PAGE_SIZE_INIT.call_once(|| match sysconf(SysconfVar::PAGE_SIZE) {
            Ok(Some(sz)) => {
        
    
pub fn host_page_size() -> usize {
    unsafe {
        HOST_PAGE_SIZE_INIT.call_once(|| match sysconf(SysconfVar::PAGE_SIZE) {
            Ok(Some(sz)) => {
                if sz as usize == HOST_PAGE_SIZE_EXPECTED {
                    HOST_PAGE_SIZE = HOST_PAGE_SIZE_EXPECTED;
                } else {
                    panic!(
                        "host page size was {}; expected {}",
                        sz, HOST_PAGE_SIZE_EXPECTED
                    );
                }
            }
            _ => panic!("could not get host page size from sysconf"),
        });
        HOST_PAGE_SIZE
    }
}