docs: function _resolveOneIdleCall(idleQueue) {
      if (idleQueue._iC.size === 0) return;
  
      const iterator = idleQueue._iC.values();
      const oldestPromise = iterator.next().value;
  
      oldestPromise._manRes();
  
      // try to call the next tick
      setTimeout(() => _tryIdleCall(idleQueue), 0);
  }