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// TState is an individual, immutable state entry in the projection state
// Flavor 1:
Projection<TState>.
  When<TEvent>.ThenAdd<TKey, TEvent>(Func<TEvent, TKey> selector, Func<TEvent, TState> handler).
  When<TEvent>.ThenUpdate<TKey, TEvent>(Func<TEvent, TKey> selector, Func<TState, TEvent, TState> handler).
  When<TEvent>.ThenAddOrUpdate<TKey, TEvent>(Func<TEvent, TKey> selector, Func<TEvent, TState> addHandler, Func<TState, TEvent, TState> updateHandler)
  When<TEvent>.ThenRemove<TKey, TEvent>(Func<TEvent, TKey> selector)

// TState is an individual, immutable state entry in the projection state  
// Flavor 2: Add & Update melted into Set leaving the host to deal with Add or Update semantics

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                Task flushingTask = null;
                
                public override Task FlushAsync(CancellationToken cancellationToken)
                {
                    Interlocked.CompareExchange(
                        ref flushingTask,
                        Task.Delay(200, cancellationToken).ContinueWith(
                            async (t) =>
                            {
                                await write.FlushAsync(cancellationToken);

yreynhout

1. General Background and Overview

• Probabilistic Data Structures for Web Analytics and Data Mining : A great overview of the space of probabilistic data structures and how they are used in approximation algorithm implementation.
• Models and Issues in Data Stream Systems
• Philippe Flajolet’s contribution to streaming algorithms : A presentation by Jérémie Lumbroso that visits some of the hostorical perspectives and how it all began with Flajolet
• Approximate Frequency Counts over Data Streams by Gurmeet Singh Manku & Rajeev Motwani : One of the early papers on the subject.
• [Methods for Finding Frequent Items in Data Streams](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.187.9800&rep

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public static class DeclarativeTSqlProjection
{
    public static void Sample()
    {
        var specification =
            TSql.Projection().
                When<StartedShopping>(@event =>
                    TSql.NonQuery(
                        "INSERT INTO [Cart] ([CartId], [Started], [Ended]) VALUES (@CartId, @Started, NULL)",
                        new

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        //FromAsync variant that can be used with APM across M<arshaling boundaries (you make your own TArgX overloads, please)
        
        static class MarshalTask 
        {
            public static Task<TResult> FromAsync<TArg1, TArg2, TResult>(Func<TArg1, TArg2, AsyncCallback, object, IAsyncResult> beginFunc, Func<IAsyncResult, TResult> endFunc, TArg1 arg1, TArg2 arg2)
            {
                var cp = new Completer<TResult>(endFunc);
                var tcs = new TaskCompletionSource<TResult>();
                cp.TaskCompletionSource = tcs;

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using NUnit;

[TestFixture]
public class ShowCase
{
    [Test]
    public void EnrichesChangedOpeningHoursInTheExpectedWay() 
    {
        new EventEnricherAssertion<BeautyFarmEventEnricher, ChangedOpeningHours>().
            SetBeautyFarmName(123, "Spa Deluxe").

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[TestFixture]
public class SomeProjectionTests 
{
    [Test]
    public void HandlesSomeEventAsExpected() 
    {
        new TSqlProjectionScenario(TSqlProjection projection). //after renaming TSqlProjectionSpecification to TSqlProjection ;-)
            Given(params object[] events).
            Given(IEnumerable<object> events).
            GivenNone().

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using Projac;
using Projac.Testing;
using Projac.Testing.NUnit;
using NUnit.Framework;

[TestFixture]
public class PortfolioProjectionTests
{
    [Test]
    public void PhotoCountIsDecrementedWhenPhotoIsRemoved() 

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[Test]
public void EqualityMembersOverridden()
{
    new EqualityMembersOverriddenAssertion(Func<object> sutFactory).
        EqualsCase(object other).
        EqualsCase(object other).
        NotEqualsCase(object other).
        NotEqualsCase(object other).
        NotEqualsCase(object other).
        Verify();

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[TestFixture]
public class AuthorizationSpecifications 
{
    [Test]
    public void WhoAreYouGonnaCall() 
    {
        new AuthorizationScenario().
            Given(events).
            When(command).
            InvokedBy(subject/identity).