Function mmap 

pub unsafe fn mmap(
    addr: *mut u8,
    len: usize,
    prot: u32,
    flags: u32,
    fd: RawFd,
    off: usize,
) -> Result<Mmap>

Maps a chunk of memory.

Safety

If the map is a shared file map, then the application must be careful about potential undefined behavior if the underlying file can change, in or out of process.