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TCP vs. UDP

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User Datagram Protocol (UDP) is often compared to TCP, as they are both transport layer protocols. Here are the high-level differences between the two:

	TCP	UDP
Connection	Yes	No
Handshake	Yes	No
In Order	Yes	No
Blazingly Fast	No	Yes

TCP establishes a connection between sender and receiver with a handshake, and ensures that all the data is sent in order. UDP yeets the data to the receiver and hopes they can make sense of it.

There are a lot of good TCP/UDP memes...

Assignment

Move your main.go file into a cmd/tcplistener directory. We're going to have a few different programs in this course, so we need to keep things organized.
Run your TCP listener, this time you'll probably want to use go run ./cmd/tcplistener
In a separate terminal run nc -v localhost 42069. You should see a "connection accepted" message.
Kill both programs with Ctrl+C.
Run nc -v localhost 42069 again, this time with your server turned off. You should see a "connection refused" message.

That's because TCP requires a connection to be established before data can be sent! UDP has no such requirement.
Run your program again and redirect the output to a temporary file:
```
go run ./cmd/tcplistener | tee /tmp/tcplistener.txt
```

Run and submit the CLI tests.