async -- C# Keyword

async  -- C# Keyword

• This Keyword is implemented from VS 2012.
•         Use the async modifier to specify that a method, lambda expression, or anonymous method is asynchronous.
•         If you use this modifier on a method or expression, it's referred to as an async method.

public async Task<int> ExampleMethodAsync()
{
    // . . . .

}

in -- C# Keyword

in -- C# Keyword

•    This Keyword is implemented from VS 2010.
•    The in keyword specifies that the type parameter is contravariant.
•    You can use the in keyword in generic interfaces and delegates.

// Contravariant interface.

interface <Interface Name><in A> { }