Run 3 consul agent on local ports: 127.0.0.1:8500, 127.0.0.1:8501, 127.0.0.1:8502.
Then run 3 example processes in separate terminal sessions:
# Terminal 1
export CONSUL_ADDR=127.0.0.1:8500
go run main.go
# Terminal 2
export CONSUL_ADDR=127.0.0.1:8501
go run main.go
# Terminal 3
export CONSUL_ADDR=127.0.0.1:8502
go run main.go