feat: sqlchannel support switchover and failover

[xuriwuyun]

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@2d2fb47). Click here to learn what that means.
Patch has no changes to coverable lines.

❗ Current head 5f18905 differs from pull request most recent head 666a2ac. Consider uploading reports for the commit 666a2ac to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3767   +/-   ##
=======================================
  Coverage        ?   73.24%           
=======================================
  Files           ?       32           
  Lines           ?     2717           
  Branches        ?        0           
=======================================
  Hits            ?     1990           
  Misses          ?      596           
  Partials        ?      131           

Flag	Coverage Δ
unittests	73.24% <ø> (?)

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