avoid type confusion between protocol.PacketType and logging.PacketType

[marten-seemann]

The enums have completely different meanings. protocol.PacketType only defines long header types, whereas logging.PacketType defines all different types of QUIC packets (including short header packets).

This led to a bug in metrics implementation in libp2p: There, we were doing something along those lines:

func (m *tracer) getEncLevel(hdr *logging.ExtendedHeader) string {
	if hdr.Type == logging.PacketType0RTT {
		return "0-RTT"
	}
        // ....
}

This leads to wrong results, as hdr.Type is a protocol.PacketType and not a logging.PacketType. It just compiled because we defined logging.PacketType as an alias for protocol.PacketType. With this PR, the code snippet above will fail to compile.

[codecov]

Codecov Report

Merging #3108 (e9b4f9b) into master (81d16a9) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3108      +/-   ##
==========================================
+ Coverage   85.47%   85.48%   +0.01%     
==========================================
  Files         131      131              
  Lines        9650     9650              
==========================================
+ Hits         8248     8249       +1     
+ Misses       1034     1033       -1     
  Partials      368      368              

Impacted Files	Coverage Δ
internal/utils/rand.go	75.00% <0.00%> (+12.50%)	⬆️

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[lucas-clemente]

IIRC we initially did this because the protocol pkg is internal, so you wouldn't be able to use APIs with PacketTypes. Is that not an issue anymore?

[marten-seemann]

That's not an issue when we set an alias, as we do for many other types.
The issue here is that the values defined for the logging.PacketType and the protocol.PacketType are different. For example, the protocol.PacketType doesn't define a type for short header packets.