ParallelForEach<T> Class

// invite all vendors and wait for their proposals 
new ParallelForEach<Vendor>
{
    DisplayName = "Get vendor proposals",
    Values = new InArgument<IEnumerable<Vendor>>(ctx =>this.Rfp.Get(ctx).InvitedVendors),
    Body = new ActivityAction<Vendor>()
    {                                    
        Argument = iterationVariableVendor,
        Handler = new Sequence
        {
            Variables = { tmpValue },
            Activities =
            {
                // waits for a vendor proposal (creates a bookmark for a vendor) 
                new WaitForVendorProposal 
                { 
                    VendorId = new LambdaValue<int>(ctx =>iterationVariableVendor.Get(ctx).Id) ,
                    Result = new OutArgument<double>(tmpValue)
                },

                // after the vendor proposal is received, it is registered in the Request for Proposals 
                new InvokeMethod
                {
                    TargetObject = new InArgument<RequestForProposal>(ctx =>this.Rfp.Get(ctx)),
                    MethodName = "RegisterProposal",
                    Parameters = 
                    {
                        new InArgument<Vendor>(iterationVariableVendor),
                        new InArgument<double>(tmpValue)
                    }
                },
            }
        }                        
    }
},