OkHttp's cache initialization is blocking the UI.
As per this trick: https://www.zacsweers.dev/dagger-party-tricks-deferred-okhttp-init/,
it should be better to initialize OkHttp in Retrofit's `callFactory` method.
This currently doesn't solve the issue with coroutines but has no downside either.
Indeed, the `callFactory` SAM is called on the `Dispatcher` which initiate the call.
It's often the `viewModelScope` which is using `Dispatchers.Main`.
Hopefully, an update to Retrofit will solve this issue.