code: public final B healthCheckIntervalMillis(long healthCheckIntervalMillis) {
          checkArgument(healthCheckIntervalMillis >= 0,
                        "healthCheckIntervalMillis: %s (expected: >= 0)", healthCheckIntervalMillis);
          healthCheckInterval = Duration.ofMillis(healthCheckIntervalMillis);
          return self();
      }
docs: Sets the interval between health check requests in milliseconds. The default value is
  {@value #DEFAULT_HEALTH_CHECK_INTERVAL_MILLIS} milliseconds.
  
  @param healthCheckIntervalMillis the interval between health check requests in milliseconds.
  {@code 0} disables health check requests.