Asynchronous lambdas

Asynchronous lambdas are useful if you want to pass a potentially long-running delegate into a method. If the method accepts a Func<Task>, you can serve it with an asynchronous lambda and take advantage of the benefits of asynchrony.

Example with Microsoft's Dataflow API.

Synchronous lambdas

var block = new ActionBlock<int> (
	i => 
	{
		Thread.Sleep(1000);
		Console.Write($"{i} ");
	},
	new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 10 }
);        

Asynchronous lambdas

var block = new ActionBlock<int> (
	async i => 
	{
		await Task.Delay (1000);
		Console.Write($"{i} ");
	},
	new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 10 }
);