Use CachedUniquePtr in Trk::AlignTrack
http://goetz.web.cern.ch/goetz/mutable_2019-07-13.html#Other_Align
nightly/master/2019-07-13T2149:Tracking/TrkAlignment/TrkAlignEvent/TrkAlignEvent/AlignTrack.h +258
256 double * m_trackAlignParamQuality; //!> describes the quality of contribution to track to alignment parameter (used by shifting derivatives)
257
258 mutable Trk::Track * m_trackWithoutScattering; //!> the original track with ScatteringAngle pointers set to 0 (called for refit so scattering will be recalculated)
259
260 }; // end class