[BUG] Spurious test failure in networking integration test

I'm seeing a test failure sometimes that looks like this: unexpected connection data: qemu-system-aarch64: terminating on signal 15 from pid 184 () I think this is because, now that the nc command in the networking integration test has a timeout, it's possible for it to time out after having opened the connection, but before having written all its input to it. I think the test should therefore ignore connections that send a prefix of the expected data (including nothing), and just wait for the next connection rather than failing if that happens.