MemoryCache.Default在.NET Core中不可用？

I'm porting some code from .NET 4.6 til .NET Core and have run into some problems with MemoryCache. The 4.6 code is using MemoryCache.Default to instantiate the cache, but this doesn't seem to be available in .NET Core. Is there any equivalent to this in .NET Core or should I rather new up my own MemoryCache as a singleton and inject it via IOC?I'm porting some code from .NET 4.6 til .NET Co