twice

import xlld.test.util: asyncReturn, newAsyncHandle;
import xlld.conv.from: fromXlOper;
import core.time: MonoTime;
import core.thread;

const start = MonoTime.currTime;
auto asyncHandle = newAsyncHandle;
auto oper = (3.2).toXlOper(theGC);
wrapAsync!twice(theGC, cast(immutable)asyncHandle, oper);
const expected = 6.4;
while(asyncReturn(asyncHandle).fromXlOper!double(theGC) != expected &&
      MonoTime.currTime - start < 1.seconds)
{
    Thread.sleep(10.msecs);
}
asyncReturn(asyncHandle).shouldEqualDlang(expected);