code: boolean isKeepaliveAllowed(long connectionStartTime)
    {
      if (! _lifecycle.isActive()) {
        return false;
      }
      else if (connectionStartTime + _keepaliveTimeMax < CurrentTime.currentTime()) {
        return false;
      }
      else if (_keepaliveMax <= _keepaliveAllocateCount.get()) {
        return false;
      }
      /*
      else if (_connThreadPool.isThreadMax()
               && _connThreadPool.isIdleLow()
               && ! isKeepaliveAsyncEnabled()) {
        return false;
      }
      */
      else {
        return true;
      }
    }
docs: Allocates a keepalive for the connection.
  
  @param connectionStartTime - when the connection's accept occurred.