.NET async Main method thread

Question

I am just wondering in an app without a SynchronizationContext (eg Console), how is async static Main(args) implemented. Is the start of the main method before any await a

1. Threadpool thread, where the CLR itself has a dedicated thread which queues Main call onto the threadpool and synchronously waits for it to finish?

   OR

2. Is it a dedicated starter thread, which gets compiled into a special state machine, to synchronously block the thread at each await. Or even maybe all await s get combined into one and the main thread waits for this combined task to complete?

Answer 1

An async static Task Main method really just generates an entry point like this:

public static void GeneratedEntryPoint(string[] args)
{
    Main(args).GetAwaiter().GetResult();
}

So just like a normal synchronous Main method, it starts in a thread with no synchronization context. That means any continuations are executed on thread-pool threads. But the initial thread (which will execute any code until the first await expression that needs to schedule a continuations) is not a thread-pool thread itself.