Cryptography has crept into everything, from web browsers and email programs to cell phones, bank cards, cars and even into medical implants. Thus, an increasing number of people have to understand how crypto schemes work and how they can be used in practice. We wanted to create a book that teaches modern applied cryptography to readers with a technical background but without an education in pure mathematics.  

• VS2019 Preview 4 broke conditional compilation symbols in C#
• API has been deprecated
• Android debugging not working in latest release 16.4 "Debuggee returned error code INVALID_ARGUMENT"
• Fixed a frequent UI delay that can occur while using the editor.
• Fixed a crash when an attribute constructor is decorated with itself and Nullable Reference Types is enabled while using C#.
• Fixed an issue that resulted in Visual Studio failing to start or crashing on C# solution load on certain Virtual Machine setups.
• Fixed a bug where user defined conditional compliation symbols are lost when the build properties page is reopened. 

The toolkit contains various controls (labesl, text entry, buttons, radio buttons, checkboxes, dialog boxes, windows, menus) for building text user interfaces, a main loop, is designed to work on Curses and the Windows Console, works well on both color and monochrome terminals and has mouse support on terminal emulators that support it.  

One thing that keeps amazing me is how many smart developers still feel the urge to write their own data access layer (DAL). They either do it all manually, or they generate parts of it, or they generate the whole thing. Whichever way you go, there are still various alternative paths you can choose from.  

Starting from Team Foundation Server 2017, the Code Search feature that was available for a while in VSTS, gets an on-premise equivalent.
The feature is built on top of a customized version of ElasticSearch. However the integration between the 2 products(TFS and ElasticSearch) is rather limited right now.

Error CS1579 foreach statement cannot operate on variables of type ‘IEnumerator’
because ‘IEnumerator’ does not contain a public instance or extension definition for ‘GetEnumerator’

static class Extensions
{
   public static IEnumerator<T> GetEnumerator<T>(this IEnumerator<T> enumerator) => enumerator;
}

class Program
{
    void Main()
    {
        var enumerator = Enumerable.Range(0, 10).GetEnumerator();
        foreach (var item in enumerator)
        {
            Console.WriteLine(item);
        }
    }
}

static class Extensions
{
    public static IAsyncEnumerator<T> GetAsyncEnumerator<T>(this IAsyncEnumerator<T> enumerator) => enumerator;
}

class Program
{
    static async Task Main()
    {
        var enumerator = GetAsyncEnumerator();
        await foreach (var item in enumerator)
        {
            Console.WriteLine(item);
        }
    }

    static async IAsyncEnumerator<int> GetAsyncEnumerator()
    {
        yield return 0;
        await Task.Delay(1);
        yield return 1;
    }
}

class Program
{
    static void Main()
    {
        foreach (var item in (1, 2, 3))
        {
            Console.WriteLine(item);
        }
    }
}

foreach statement cannot operate on variables of type '(int, int, int)'
because '(int, int, int)' does not contain a public instance or extension definition
for 'GetEnumerator' [CS9Features]csharp(CS1579)

static class Extensions
{
    public static IEnumerator<object> GetEnumerator<T1, T2, T3>(this ValueTuple<T1, T2, T3> tuple)
    {
        yield return tuple.Item1;
        yield return tuple.Item2;
    }
}

For a year and a half we ran an Early Access Program (EAP) for this product while it was still known as 0xDBE. At some point one needs to stop and draw the line 

Once created, these custom elements -- a custom counter, for example -- can also be used in other single-page application (SPA) web frameworks such as React and Angular. A sample project, aptly titled Blazor Custom Elements, shows how to do just that, providing examples about how to work with those frameworks and the client-side Blazor WebAssembly component as well as Blazor Server.