foldLeftWithIndex<B> method
Implementation
@override B foldLeftWithIndex<B>(B z, B f(B previous, int i, A a)) {
var i = 0;
var result = z;
var current = this;
while (current._isCons()) {
result = f(result, i++, current._unsafeHead());
current = current._unsafeTail();
}
return result;
}