tx.send_to(&[0u8], None) fail

[yunfengwangluo]

let (mut tx, mut rx) = match datalink::channel(&selected_interface, Default::default()) { Ok(datalink::Channel::Ethernet(tx, rx)) => (tx, rx), Ok(_) => panic!("未处理的通道类型"), Err(e) => panic!("创建通道失败: {}", e), }; tx.send_to(&[0u8], None).unwrap().unwrap();
called Result::unwrap() on an Err value: Os { code: 21, kind: Uncategorized, message: "设备未就绪。" }

Thank you for wasting your valuable time looking at my question. Thank you again!

According to the description of this function, the second parameter is currently ignored and should be used as' None ', but I encountered the above error after doing so. I don't know if there is a problem with my usage!