> - a tee loadbalancer for gRPC, forwarding the same requests to both A and B backend pools, but only returning results from A. I don't think Envoy has this, but it should.
Envoy can do this, via its shadowing feature. See the docs here: https://www.envoyproxy.io/docs/envoy/v1.6.0/api-v2/api/v2/ro....