udp: allows to create ClientConn at server

[jkralik]

Fixes #315

[codecov-commenter]

Codecov Report

Merging #316 (4e9474f) into master (96978f2) will decrease coverage by 0.13%.
The diff coverage is 78.94%.

@@            Coverage Diff             @@
##           master     #316      +/-   ##
==========================================
- Coverage   69.28%   69.15%   -0.14%     
==========================================
  Files          67       67              
  Lines        5571     5583      +12     
==========================================
+ Hits         3860     3861       +1     
- Misses       1312     1320       +8     
- Partials      399      402       +3     

Impacted Files	Coverage Δ
udp/server.go	83.09% <78.94%> (-0.99%)	⬇️
net/conn.go	82.81% <0.00%> (-3.13%)	⬇️
udp/client/clientconn.go	70.81% <0.00%> (-0.96%)	⬇️
tcp/clientobserve.go	66.38% <0.00%> (-0.85%)	⬇️

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[ihidchaos]

Can you merge it to the master branch?

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

81.2% Coverage
0.0% Duplication