pub fn splice(fd_in: RawFd, off_in: Option<&mut libc::loff_t>, fd_out: RawFd, off_out: Option<&mut libc::loff_t>, len: usize, flags: SpliceFFlags) -> Result<usize>
The portability is definied by: #[cfg(any(target_os = "linux", target_os = "android"))]