C# Decimal reinterpret as longs and back

using System;
using System.Runtime.InteropServices;

namespace Example {

   /// <summary>
   /// Each instance must be used in single thread
   /// </summary>
   class DecimalBitConverter {

      [StructLayout(LayoutKind.Explicit)]
      struct OverlapData {
         [FieldOffset(0)] public Decimal decimalValue;
         [FieldOffset(0)] public Int64 int64_0;
         [FieldOffset(8)] public Int64 int64_1;
      }

      OverlapData _temp = new OverlapData();

      public Decimal ToDecimal(Int64 i0, Int64 i1) {
         _temp.int64_0 = i0;
         _temp.int64_1 = i1;
         return _temp.decimalValue;
      }

      public Decimal ToDecimal(Tuple<Int64, Int64> x) {
         return ToDecimal(x.Item1, x.Item2);
      }

      public Tuple<Int64, Int64> ToLongs(Decimal x) {
         _temp.decimalValue = x;
         return Tuple.Create(_temp.int64_0, _temp.int64_1);
      }
   }

   class Test {
      private static void Main(string[] args) {
         var x = 42.0042m;
         var converter = new DecimalBitConverter();
         var t = converter.ToLongs(x);
         Console.WriteLine(t);
         var y = converter.ToDecimal(t);
         Console.WriteLine(y);
      }
   }
}