Throttle NServiceBus throughput when a custom check fails using service control custom checks

ThrottleThroughputWhenCheckFailsUsingPeriodicCheck.cs

using System;
using NServiceBus;
using NServiceBus.Logging;
using ServiceControl.Plugin.CustomChecks;

class ThrottleThroughputWhenCheckFails : PeriodicCheck
{
    NServiceBus.Unicast.UnicastBus bus;
    ILog Log = LogManager.GetLogger(typeof(IntegrationCustomCheck));

    bool throttled;
    int throttledLimit = 1;
    int unthrottledLimit = 0;

    public IntegrationCustomCheck(IBus bus)
        : base("Custom check", "Integration", TimeSpan.FromSeconds(5))
    {
        this.bus = (NServiceBus.Unicast.UnicastBus)bus;
    }

    int count;

    bool Check()
    {
        return count++ % 4 == 0;
    }

    public override CheckResult PerformCheck()
    {
        var result = Check();

        Log.DebugFormat("Check: {0}", result);
        Log.DebugFormat("Throttled: {0}", throttled);

        var transport = bus.Transport;

        if (result && throttled)
        {
            transport.ChangeMaximumMessageThroughputPerSecond(unthrottledLimit);
            throttled = false;
            Log.InfoFormat("Disabled throttling");
        }

        if (!result && !throttled)
        {
            transport.ChangeMaximumMessageThroughputPerSecond(throttledLimit);
            throttled = true;
            Log.InfoFormat("Enabled throttling");
        }

        if (result)
            return CheckResult.Pass;
        else
            return CheckResult.Failed("Check failed");
    }
}