fix(udp): retry on ErrorKind::Interrupted

[mxinden]

On Linux and Android, quinn-udp will retry a send on ErrorKind::Interrupted:

quinn/quinn-udp/src/unix.rs

Lines 305 to 312 in e318cc4

	loop {
	let n = unsafe { libc::sendmsg(io.as_raw_fd(), &msg_hdr, 0) };
	if n == -1 {
	let e = io::Error::last_os_error();
	match e.kind() {
	io::ErrorKind::Interrupted => {
	// Retry the transmission
	continue;

Do the same on all other unix platforms.

[Ralith]

Thanks!

[djc]

Just needs rebasing!