public static async Task ShutdownPoolAsync(string connectionString)
{
// Give this session pool up to 10 seconds to shut down, so we delete the extra sessions
// and stop its maintenance loop.
using (var connection = new SpannerConnection(connectionString))
{
var cancellationToken = new CancellationTokenSource(10000).Token;
await connection.ShutdownSessionPoolAsync(cancellationToken);
}
}