Why synchronous IDisposable.Dispose() causes thread deadlocks in asynchronous classes:

If closing a network socket or flushing a buffered stream requires an async I/O call (stream.FlushAsync()), calling .Result inside Dispose() can cause thread pool starvation deadlocks.

The Solution: IAsyncDisposable:

public class AsyncResourceClient : IAsyncDisposable
{
    public async ValueTask DisposeAsync()
    {
        if (_networkStream != null)
        {
            await _networkStream.FlushAsync();
            await _networkStream.DisposeAsync();
        }
    }
}

// Consumer
await using (var client = new AsyncResourceClient())
{
    await client.DoWorkAsync();
}

await using ensures all async flushes complete cleanly before the resource is destroyed.

Always prefer returning ValueTask from DisposeAsync to keep synchronous disposal zero-allocation.