response_headers {
  headers {
    key: "endpoint-load-metrics"
    # This decodes and deserializes to the following proto:
    # cpu_utilization: 0.4
    # rps_fractional: 50
    # named_metrics {
    #  key: "foo"
    #  value: 0.5
    # }
    value: "BIN CZqZmZmZmdk/MQAAAAAAAElAQg4KA2ZvbxEAAAAAAADgPw=="
  }
}
