Challenge 3: A using Declaration Disposing Despite an Exception — Possible Solution
====================================================================

Program.cs:

class NoisyResource : IDisposable
{
    public void Dispose() => Console.WriteLine("Dispose() called.");
}

static void RunDemo()
{
    using var resource = new NoisyResource();   // using DECLARATION -- no braces
    Console.WriteLine("Inside the scope.");
    throw new InvalidOperationException("Something went wrong!");
    // no code after this point in the method runs
}

try
{
    RunDemo();
}
catch (InvalidOperationException e)
{
    Console.WriteLine("Caught: " + e.Message);
}

Output:

    Inside the scope.
    Dispose() called.
    Caught: Something went wrong!

Explanation:
`using var resource = ...;` is C# 8's using DECLARATION form -- there
are no braces marking an explicit scope the way java1-7's own
try-with-resources requires. Instead, resource is disposed
automatically at the end of the ENCLOSING scope, which here is the end
of RunDemo() itself. Even though an exception is thrown before the
method reaches its natural end, Dispose() still runs during the
method's exit (as the exception propagates out), BEFORE the exception
reaches the outer catch block -- confirmed by the output order.

WHY THIS WORKS AS AN ANSWER
------------------------------
This demonstrates the using declaration's more concise, brace-free
syntax compared to java1-7's own try(...) block form, while confirming
it provides the identical guarantee -- Dispose()/close() runs even
when an exception is thrown before the scope ends normally.