This project reproduces performance issue with using AutoFixture to create large record types.

Command to test performance

dotnet clean && dotnet build  && time dotnet test

Testing two scenarios, with OmitAutoPropertiesForRecordTypes Customization added and without. My own testing in this project showed that by omiting auto properties for record types, I get performance bump from ~400 seconds to about 10.

P.S. I am assuming that CompilerGeneratedAttribute marks all the properties of record type so I have a solution wide workaround, instead of going through each type and customizing with OmitAutoProperties().