将。net 4的线程化为。net 2

I am using someone else's .NET 4 open source smoothed particle hydrodynamics code and I'm trying to convert it for a Unity project which you can only count on to be up to .NET 2 standards. Unfortunately the code uses the Parallels class (which is awesome!) but he used one of the more obscure overloads. Can anyone see a good way to achieve the same thing in .NET 2 without a huge performance hit?I am using someone else's .NET 4 open source sm