Function sys_sendto 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn sys_sendto(
    fd: i32,
    buf: *const u8,
    len: usize,
    _flags: i32,
    addr: *const sockaddr,
    addr_len: socklen_t,
) -> isize

Available on crate features net or virtio-vsock only.