add static func for encode message to byte

[szpnygo]

#38

[codecov]

Codecov Report

Merging #39 (a8abba0) into main (4e809ac) will decrease coverage by 0.22%.
The diff coverage is 50.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #39      +/-   ##
==========================================
- Coverage   62.25%   62.03%   -0.23%     
==========================================
  Files          67       68       +1     
  Lines        2840     2876      +36     
==========================================
+ Hits         1768     1784      +16     
- Misses        933      952      +19     
- Partials      139      140       +1     

Impacted Files	Coverage Δ
message/static.go	0.00% <0.00%> (ø)
session/static.go	7.14% <0.00%> (-4.63%)	⬇️
agent/agent.go	53.03% <40.00%> (-1.59%)	⬇️
agent/factory.go	81.08% <100.00%> (+0.52%)	⬆️
app.go	84.90% <100.00%> (+0.14%)	⬆️
packet/packet.go	96.25% <100.00%> (+0.86%)	⬆️