Document how CompositeActivity Build behaves

When programming composite activities it is essential one understands how Build method of CompositeActivity behaves, actually when it gets invoked. And when do the various callbacks inside Build method of CompositeActivity get invoked.

I believe following code tells the whole picture, would be grateful if you could document it fully including how many times and **when** Build method will be invoked.

public override void Build(ICompositeActivityBuilder builder)
{
Console.WriteLine("Invoked several times at workflow instance initialization and at bookmark indexing, CompositeActivity properties not available!");
builder.Then(setup =>
{
Console.WriteLine("Invoked several times at workflow instance initialization and at bookmark indexing, CompositeActivity properties not available!");
setup.WithText(context => {
Console.WriteLine("Ivoked once each time Composite activity is executed, CompositeActivity properties are available :).");
return "Testing";
});
}