For web sockets, this requires substantial infrastructure changes. In the meantime, we recommend Cloud Run for Anthos, which supports web sockets.
Cool. Can you please tell us how to setup Anthos? From an availability perspective, it is "Contact Sales" vaporware.
You can currently use Cloud Run for Anthos with no additional charge beyond GKE until May 2020. After that, you'd need an Anthos subscription to continue using the product.
I agree that it's frustrating that you have to contact sales to sign up. We're working to make this self-serve in the future -- Anthos hasn't been available for very long, and we plan to make substantial improvements here.