Pelador request, patching with transpiler.

Pelador.cs

using System.Collections.Generic;
using Verse;
using RimWorld;
using Harmony;
using System.Reflection;
using System.Linq;
using System.Reflection.Emit;

public class CustomAction
{
    public delegate void RefAction<T1, T2, T3>(ref T1 t1, T2 t2, T3 t3);
}
//or use this
//public delegate void RefAction<T1, T2, T3>(ref T1 t1, T2 t2, T3 t3);

public static class Patch_WorkGiver_DoBill
{
    static MethodBase GetBillGiverRootCell = AccessTools.Method(typeof(WorkGiver_DoBill), "GetBillGiverRootCell");
    static FieldInfo newReleventThingsFieldInfo = AccessTools.Field(typeof(WorkGiver_DoBill), "newRelevantThings");
    static CustomAction.RefAction<List<Thing>, Thing, IntVec3> refAction;
    static Thing billGiver;
    static Pawn pawn;
    static IntVec3 rootCell;
    public static void DoPatch(HarmonyInstance HMinstance, CustomAction.RefAction<List<Thing>, Thing, IntVec3> refAction)
    {
        var original = AccessTools.Method(typeof(WorkGiver_DoBill), "<>m__3");
        var prefix = AccessTools.Method(typeof(Patch_WorkGiver_DoBill), "Prefix_ResourceGetter");
        var transpiler = AccessTools.Method(typeof(Patch_WorkGiver_DoBill), "Transpiler_bracket_m__3");
        HMinstance.Patch(original, new HarmonyMethod(prefix), null, new HarmonyMethod(transpiler));
        
        Patch_WorkGiver_DoBill.refAction = refAction;
    }

    static void Prefix_ResourceGetter(Pawn pawn, Thing billGiver)
    {
        Patch_WorkGiver_DoBill.billGiver = billGiver;
        Patch_WorkGiver_DoBill.pawn = pawn;
    }


    static void MethodInvoker(ref List<Thing> newReleventThings)
    {
        var rootCell = (IntVec3)GetBillGiverRootCell.Invoke(null, new object[] { billGiver, pawn });
        refAction.Invoke(ref newReleventThings, billGiver, rootCell);
    }

    static IEnumerable<CodeInstruction> Transpiler_bracket_m__3(IEnumerable<CodeInstruction> instructions)
    {
        var invokeMethod = AccessTools.Method(typeof(Patch_WorkGiver_DoBill), "MethodInvoker");
        var insts = instructions.ToList();
        int instsCount = insts.Count;
        for(int i = 0; i < instsCount; i++)
        {
            var inst = insts[i];
    
            if(i > 0 && i < instsCount - 1 && insts[i-1].opcode == OpCodes.Ble && inst.opcode == OpCodes.Ldarg_0 && insts[i+1].operand?.ToString().Contains("<>m__4") == true)
            { // entering line 739, IL, DnSpy
                yield return new CodeInstruction(OpCodes.Ldsflda, newReleventThingsFieldInfo);
                yield return new CodeInstruction(OpCodes.Call, invokeMethod);
                i += 6;
                continue; // jump to line 745, callvirt Sort. next invoking line is 746 ldsfld.
            }
    
            yield return inst;
        }
    }

    //Patch Example
    static void Patch()
    {
        DoPatch(null, Do_Work);
    }
    
    //Method Example
    static void Do_Work(ref List<Thing> things, Thing thing, IntVec3 intVec3)
    {
        //do something... ok?
    }
    //wrote by madeline#1941
}