Instrumented stash receive actor

InstrumentedStashReceiveActor.cs

/// <summary>
/// ReceiveActor with unbounded stash implementation that sends stash depth metrics with AppMetrics.
/// Use when you wish to monitor the stash depth with reporting tools such as DataDog.
/// </summary>
public abstract class InstrumentedStashReceiveActor : ReceiveActor, IWithUnboundedStash
{
private int _stashSize = 0;

private static readonly GaugeOptions GaugeOptions = new GaugeOptions
{
    Name = "akka.actor.stash.depth",
};

private readonly MetricTags _metricTags;

protected InstrumentedStashReceiveActor()
{
    this._metricTags = new MetricTags(
        new[] { AppMetricsTagKeys.ActorType, AppMetricsTagKeys.AkkaAddress },
        new[] { this.GetType().FullName, Cluster.Get(Context.System).SelfAddress.ToString() });
}

IStash IActorStash.Stash { get; set; }

protected void AddToStash()
{
    ((IWithUnboundedStash)this).Stash.Stash();
    this._stashSize++;

    this.SetGaugeValue();
}

protected void UnstashAll()
{
    ((IWithUnboundedStash)this).Stash.UnstashAll();
    this._stashSize = 0;

    this.SetGaugeValue();
}

private void SetGaugeValue()
{
    Context.GetInstrumentation().Monitor.Gauge.SetValue(GaugeOptions, this._metricTags, this._stashSize);
}

private static class AppMetricsTagKeys
{
    public const string ActorType = "actortype";

    public const string AkkaAddress = "akka_address";
}