Nullable examples

[Kielek]

Towards #894

Changes

Please provide a brief description of the changes here.

For significant contributions please make sure you have completed the following items:

• [ ] Appropriate CHANGELOG.md updated for non-trivial changes
• [ ] Design discussion issue #
• [ ] Changes in public API reviewed

[codecov]

Codecov Report

Merging #1357 (951cc9f) into main (b3c7ae7) will increase coverage by 0.00%.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1357   +/-   ##
=======================================
  Coverage   73.85%   73.86%           
=======================================
  Files         266      266           
  Lines        9598     9596    -2     
=======================================
- Hits         7089     7088    -1     
+ Misses       2509     2508    -1     

Files Changed	Coverage
...ntation.Hangfire/HangfireInstrumentationOptions.cs	ø
...tation.Hangfire/TracerProviderBuilderExtensions.cs	ø
...ation/HangfireInstrumentationJobFilterAttribute.cs	100.00%