static <A> WithSideValue<FunctionResourceUse, A> evaluateWithResourceUse(IF0<A> f) {
  long time1 = nanoTime();
  long value1 = bytesAllocatedByCurrentThread();
  A a = f?!;
  long value2 = bytesAllocatedByCurrentThread();
  long time2 = nanoTime();
  ret withSideValue(FunctionResourceUse()
    .bytesAllocated(value1 < 0 ? -1 : value2-value1)
    .runtime(nanosToSecondsObject(time2-time1)), a);
}