System.Runtime.CompilerServices.RuntimeOps.MergedRuntimeVariables.this C# (CSharp) Метод

            public object this[int index]
            {
                get
                {
                    index = _indexes[index];
                    return (index >= 0) ? _first[index] : _second[-1 - index];
                }
                set
                {
                    index = _indexes[index];
                    if (index >= 0)
                    {
                        _first[index] = value;
                    }
                    else
                    {
                        _second[-1 - index] = value;
                    }
                }
            }
        }