cache all appcontext switches

[Wraith2]

fixes #2225

Change any uncached appcontext switches to use caching like the others.

/cc @JulianRooze

[jkotas]

bool? is a structure with two fields. It is not updated atomically. The lock-free reads and writes below have race conditions.

If you want the reads to be lock-free, you can either:

• Change the type of these caches to bool and initialize them eagerly in a static constructors
  or
• Change the type of these caches to atomically updated integer with 3 possible values uninitialized/false/true. Here is an example of similar pattern in dotnet/runtime: https://github.com/dotnet/runtime/blob/b88c74a109903de213b049177cbc0481a689477f/src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs#L22C22-L27

[Wraith2]

Thanks. I've updated all the variables to use the tristate enum pattern.

[jkotas]

Failing tests:

  [xUnit.net 00:01:04.53]       System.InvalidCastException : Unable to cast object of type 'Tristate' to type 'System.Nullable`1[System.Boolean]'.
  [xUnit.net 00:01:04.53]       Stack Trace:
  [xUnit.net 00:01:04.53]         D:\a\_work\1\s\src\Microsoft.Data.SqlClient\tests\ManualTests\SQL\DataReaderTest\DataReaderTest.cs(330,0): at Microsoft.Data.SqlClient.ManualTesting.Tests.DataReaderTest.SetLegacyRowVersionNullBehavior(Nullable`1 value)
  [xUnit.net 00:01:04.53]         D:\a\_work\1\s\src\Microsoft.Data.SqlClient\tests\ManualTests\SQL\DataReaderTest\DataReaderTest.cs(301,0): at Microsoft.Data.SqlClient.ManualTesting.Tests.DataReaderTest.CheckLegacyNullRowVersionIsEmptyArray()

[Wraith2]

Thanks. Fixed and added note to tests and source to indicate that private reflection is being used. I wrote that test so I should have remembered.

[codecov]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (d30d9d1) 71.49% compared to head (f1243c0) 68.34%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
...icrosoft/Data/SqlClient/LocalAppContextSwitches.cs	64.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2227      +/-   ##
==========================================
- Coverage   71.49%   68.34%   -3.16%     
==========================================
  Files         309      309              
  Lines       62181    62195      +14     
==========================================
- Hits        44459    42506    -1953     
- Misses      17722    19689    +1967     

Flag	Coverage Δ
addons	92.88% <ø> (ø)
netcore	65.87% <60.00%> (-8.69%)	⬇️
netfx	69.84% <64.00%> (-0.01%)	⬇️

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