Do not parse packets as utf8

[iffyio]

In some parts of session.rs and server/mod.rs we currently try to parse packets as utf8 and will fail to do so and panic with raw bytes. We likely need to remove these lines

[markmandel]

Agreed, they should probably be something more like:

"contents" => from_utf8(packet).unwrap.or_else(|| format!("<raw bytes. len: {}>", packet.len())) - or something like that

[markmandel]

You are going to laugh. I literally JUST hit this issue writing the compression filter.

Looks like I'm implementing a fix!

[iffyio]

I'm thinking it makes more sense to remove the log lines rather than work around it? Currently it seems to be unneeded work to try to parse every packet and create a log record each time only to discard it, especially since metrics tracks that info already.

[markmandel]

I honestly find it really useful when debugging issues found by integration tests, because I can see where in the flow packets are failing.

[iffyio]

I think this relates to #153 outcome in that since the log messages are only needed during development we can compile them entirely away? I'm thinking then we can log them at level trace so that they are explicitly enabled, temporarily when needed