gistfile1.cs

Method:

private Task<TextMessage> SendMessageToServiceAsync(TextMessage message)
{
    var tcs = new TaskCompletionSource<TextMessage>();

    SendMessageToService(message, (msg) => tcs.SetResult(msg));

    return tcs.Task;
}

Calling it this way:

TextMessage sentMessage = await SendMessageToServiceAsync(message);
OnMessageSentAction(sentMessage);

Getting following error:

"The 'await' operator can only be used within an async method. Consider marking this method with the 'async' modifier and changing its return type to 'Task'."

But marking the method with async, and doing 'await tcs.Task' doesn't work either. Same error.