Add server_client example

[torkleyy]

This is a stupid example, yes. I'm probably doing something wrong, because I noticed two issues:

• messages take very long (~ 1 second) until they're shown. probably some blocking going on somewhere?
• when there is no server and I send a message with the client, I don't get any error message (nothing happens)

[torkleyy]

Not meant to be merged

[TimonPost]

A lol, I also worked on examples but now I see you also did some. I noticed something too that it took long before an message was received further investigation needed.

[TimonPost]

I did some test to monitor how long it took to send a message and it took 1 second. So there is some bug somewhere :)

test results:

= Message took 72.982µs to send =
Moving to lat: 10.555, long: 10.55454, alt: 1.3
=Message took 990.276878ms to send =
Moving to lat: 5.4545, long: 3.344, alt: 1.33
= Message took 990.114451ms to send =
Received text: "Some information"

After debugging I found that create_connection_if_not_exists method takes 0.5 - 0.9 seconds to execute.

And found out that acquiring the lock on connections is taking to long in create_connection_if_not_exists method.

  let mut lock = self
            .connections
            .write()
            .map_err(|_| NetworkError::AddConnectionToManagerFailed)?;

[torkleyy]

This could be merged now. Should I add a comment to the example that it doesn't reflect the use-cases of this crate?

[TimonPost]

Nice chat example, maybe not ideal for UDP but still fun example!. Further nice fix for that bug with the lock. I have tested how fast it was but it was way faster than before so looks good to me.

[TimonPost]

???

[torkleyy]

Yes, those are result wrapped results, most likely for non-blocking stuff.

[torkleyy]

Well I'm not sure if the API is designed right here.

[torkleyy]

Ready for merge.