static HealthChecker ofCpu(double targetSystemCpuUsage, double targetProcessCpuUsage) {
        return new CpuHealthChecker(targetSystemCpuUsage, targetProcessCpuUsage);
    }
Creates a new instance of {@link HealthChecker} which reports health based on
cpu usage reported by {@link OperatingSystemMXBean}.
Both system and process cpu usage must be (inclusive) lower than the specified threshold in order
for the {@link HealthChecker} to report as healthy. If the {@link HealthChecker} is unable
to find a suitable {@link OperatingSystemMXBean}, an exception is thrown on construction.

@param targetSystemCpuUsage  Target system CPU usage as a percentage (0 - 1).
@param targetProcessCpuUsage Target process CPU usage as a percentage (0 - 1).
@return an instance of {@link HealthChecker} configured with the provided CPU usage targets.
core/src/main/java/com/linecorp/armeria/server/healthcheck/HealthChecker.java