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configureawait.linq

<Query Kind="Program">
  <Namespace>System.Threading.Tasks</Namespace>
</Query>

void Main()
{
	Client().Wait();
}

async Task Client()
{	
	SynchronizationContext.SetSynchronizationContext(new MySynchronizationContext("Client"));
	await LibCode();
}


async Task LibCode()
{
	SynchronizationContext.SetSynchronizationContext(new MySynchronizationContext("Library"));
	await Task.Run(() => {
		Console.WriteLine("Running some lib code...");
	}).ConfigureAwait(false);
}

// Output:
//  Running some lib code...
//  Called back into Client context.

// Without ConfigureAwait(false):
//  Running some lib code...
//  Called back into Library context.
//  Called back into Client context.

class MySynchronizationContext : SynchronizationContext
{
    private readonly string _name;
	
    public MySynchronizationContext(string name)
    {
        _name = name;
    }

    public override void Post(SendOrPostCallback d, object state)
    {
        Console.WriteLine("Called back into " + _name + " context.");
        base.Post(d, state);
    }
}