SQLiteInMemoryConnectionProviderAsync_correct.cs

public class SQLiteInMemoryConnectionProvider : DriverConnectionProvider
{
    private static DbConnection? _connection = null;

    public override DbConnection GetConnection()
    {
        return _connection ??= base.GetConnection();
    }

    public override async Task<DbConnection> GetConnectionAsync(CancellationToken cancellationToken)
    {
        if (cancellationToken.IsCancellationRequested)
        {
            return await Task.FromCanceled<DbConnection>(cancellationToken);
        }

        return  _connection ??= await base.GetConnectionAsync(cancellationToken);
    }

    public override void CloseConnection(DbConnection conn) { }
}