The following instructions should be followed in order to create a code coverage report locally.
dotnet tool install --global dotnet-reportgenerator-globaltool --version 5.1.4 --add-source https://www.nuget.org/packages/
avro\lang\csharp\src\apache\test
dotnet test --results-directory ./TestResults --collect:"XPlat Code Coverage"
ReportGenerator "-reports:./TestResults/*/coverage.cobertura.xml" "-targetdir:./Coverage/" -reporttypes:HTML
avro\lang\csharp\src\apache\test\Coverage\index.html