C# 8 understanding await using syntax

I have next method:

public async Task<IEnumerable<Quote>> GetQuotesAsync()
{
    using var connection = new SqlConnection(_connectionString);

    var allQuotes = await connection.QueryAsync<Quote>(@"SELECT [Symbol], [Bid], [Ask], [Digits] FROM [QuoteEngine].[RealtimeData]");

    return allQuotes;
}

Everything fine and clear, connection will be disposed at the end of scope.

But resharper suggests to change it to:

public async Task<IEnumerable<Quote>> GetQuotesAsync()
{
    await using var connection = new SqlConnection(_connectionString);

    var allQuotes = await connection.QueryAsync<Quote>(@"SELECT [Symbol], [Bid], [Ask], [Digits] FROM [QuoteEngine].[RealtimeData]");

    return allQuotes;
}

It adds await before using and code is compiled successfully. What does it mean and when do we need to do that?

Similar as using (...) uses IDisposable to clean up resources, await using (...) uses IAsyncDisposable. This allows to perform also time-consuming tasks (e.g involving I/O) on cleanup without blocking.

If SqlConnection implements IAsyncDisposable interface, Resharper suggests you to switch to await using to dispose it asynchronously using DisposeAsync method

public interface IAsyncDisposable
{
    ValueTask DisposeAsync();
}