unity smooth layer weight change
var m_currentLayerWeight = _playerAnimator.GetLayerWeight(1);
m_currentLayerWeight =Mathf.SmoothDamp(m_currentLayerWeight, IsArmed ? 1 : 0, ref _currentLayerWeightVelocity, animTransSmoothTime);
_playerAnimator.SetLayerWeight(1,m_currentLayerWeight);