Implementing Health Checking

import (
    healthpb "google.golang.org/grpc/health/grpc_health_v1"
    "google.golang.org/grpc/health"
)
h := health.NewServer()
healthpb.RegisterHealthServer(srv, h)
h.SetServingStatus("", healthpb.HealthCheckResponse_SERVING)         // overall
h.SetServingStatus("user.v1.UserService", healthpb.HealthCheckResponse_SERVING)

hc := healthpb.NewHealthClient(conn)
res, err := hc.Check(ctx, &healthpb.HealthCheckRequest{Service: "user.v1.UserService"})

stream, _ := hc.Watch(ctx, &healthpb.HealthCheckRequest{Service: "user.v1.UserService"})
for {
    r, err := stream.Recv()
    if err != nil { break }
    fmt.Println("status", r.Status)
}