Support for System.Text.Json and remove Newtonsoft

[wasimdigital]

Kindly add support for System.Text.Json and remove Newtonsoft.Json package as it is a significant performance improvement and will allow size reduction of my package

[jskeet]

This would be a huge change - a breaking change for just under 1000 NuGet packages, forcing a new major version for all of them.

We would like to do this eventually, but it's an enormous amount of work (any breaking change for Google.Apis, Google.Apis.Core or Google.Apis.Auth has widespread impact) and we don't expect to get to it any time soon.

There's more discussion in googleapis/google-api-dotnet-client#1995

I'd like to close this issue given that it's effectively a duplicate of that - I'd suggest that you subscribe to that issue to keep track of any change.

[jskeet]

Closing this issue given the comment above.