private SetChangedEventArgs(SetElementOperation op, T element, int indexBefore, int indexAfter)
{
this.op = op;
this.element = element;
this.indexBefore = indexBefore;
this.indexAfter = indexAfter;
}
SetChangedEventArgs(
SetElementOperation op,
T element,
int indexBefore,
int indexAfter)
{
_op = op;
_element = element;
_indexBefore = indexBefore;
_indexAfter = indexAfter;
}