implement keepalive feature

[jkralik]

No description provided.

[codecov-io]

Codecov Report

Merging #93 into master will increase coverage by 2.38%.
The diff coverage is 74.56%.

@@            Coverage Diff             @@
##           master      #93      +/-   ##
==========================================
+ Coverage   60.15%   62.54%   +2.38%     
==========================================
  Files          33       34       +1     
  Lines        3170     3268      +98     
==========================================
+ Hits         1907     2044     +137     
+ Misses       1058     1008      -50     
- Partials      205      216      +11

Impacted Files	Coverage Δ
error.go	100% <ø> (ø)	⬆️
networksession.go	100% <ø> (ø)	⬆️
blockwise.go	61.23% <0%> (+0.24%)	⬆️
sessiontcp.go	77.08% <100%> (+2.08%)	⬆️
servermux.go	77.46% <100%> (+2.81%)	⬆️
sessionudp.go	90% <100%> (+11.33%)	⬆️
server.go	62.5% <64.1%> (+1.85%)	⬆️
keepalive.go	69.11% <69.11%> (ø)
sessiondtls.go	67.14% <75%> (+19.77%)	⬆️
client.go	61.03% <75%> (+1.1%)	⬆️
... and 14 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 40e35a4...adadd16. Read the comment docs.