Function fadvise 

pub fn fadvise<Fd: AsFd>(
    fd: Fd,
    offset: u64,
    len: Option<NonZeroU64>,
    advice: Advice,
) -> Result<()>

posix_fadvise(fd, offset, len, advice)—Declares an expected access pattern for a file.

If len is None, the advice extends to the end of the file.

References

• POSIX
• Linux
• FreeBSD