func (*blockingPortForward) Disrupt(s string) bool {
	if s == "managedClearPort return error" {
		return true
	}
	if s == "managedForwardPort" {
		time.Sleep(time.Second * 3)
	}
	return false
}
disrupt will cause the port forward call to block for 10 seconds, but still
complete normally. disrupt will also cause managedClearPort to return an
error.
package host
import (
	"sync/atomic"
	"testing"
	"time"
	"github.com/NebulousLabs/Sia/build"
	"github.com/NebulousLabs/Sia/modules"
)
type blockingPortForward struct {
	modules.ProductionDependencies
}