opts.Parallel = runtime.GOMAXPROCS(0)
	}
	if opts.Limit > 0 && int64(opts.Parallel) > opts.Limit {
		// Don't start more workers than we need.
		opts.Parallel = int(opts.Limit)
	}

	c, err := newCoordinator(opts)
	if err != nil {
		return err
	}

	if opts.Timeout > 0 {
		var cancel func()
		ctx, cancel = context.WithTimeout(ctx, opts.Timeout)
		defer cancel()
	}