Added any_connection::connection_id

[anarthal]

close #408

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.95%. Comparing base (195623e) to head (397b6fa).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #409   +/-   ##
========================================
  Coverage    98.95%   98.95%           
========================================
  Files          142      142           
  Lines         7199     7207    +8     
========================================
+ Hits          7124     7132    +8     
  Misses          75       75           

Files with missing lines	Coverage Δ
include/boost/mysql/any_connection.hpp	100.00% <100.00%> (ø)
include/boost/mysql/detail/connection_impl.hpp	94.95% <ø> (ø)
include/boost/mysql/impl/connection_impl.ipp	100.00% <100.00%> (ø)
...t/mysql/impl/internal/protocol/deserialization.hpp	97.36% <100.00%> (+<0.01%)	⬆️
...sql/impl/internal/sansio/connection_state_data.hpp	100.00% <ø> (ø)
...ude/boost/mysql/impl/internal/sansio/handshake.hpp	92.17% <100.00%> (+0.06%)	⬆️

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 195623e...397b6fa. Read the comment docs.