ENH: ExternalData: Factor atomic file write into private function
ENH: ExternalData: Factor atomic file write into private function

Create private atomic_write function that writes content to a temporary
file name and then atomically renames it to the final location.

jmerkow/ITK,LucHermitte/ITK,PlutoniumHeart/ITK,itkvideo/ITK,hinerm/ITK,zachary-williamson/ITK,jcfr/ITK,jmerkow/ITK,Kitware/ITK,fbudin69500/ITK,thewtex/ITK,blowekamp/ITK,hjmjohnson/ITK,fbudin69500/ITK,spinicist/ITK,wkjeong/ITK,thewtex/ITK,Kitware/ITK,blowekamp/ITK,paulnovo/ITK,LucHermitte/ITK,fuentesdt/InsightToolkit-dev,fuentesdt/InsightToolkit-dev,biotrump/ITK,richardbeare/ITK,richardbeare/ITK,atsnyder/ITK,hinerm/ITK,eile/ITK,LucHermitte/ITK,wkjeong/ITK,jmerkow/ITK,jmerkow/ITK,PlutoniumHeart/ITK,biotrump/ITK,spinicist/ITK,zachary-williamson/ITK,LucasGandel/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,LucHermitte/ITK,stnava/ITK,CapeDrew/DCMTK-ITK,vfonov/ITK,hendradarwin/ITK,ajjl/ITK,paulnovo/ITK,fedral/ITK,BRAINSia/ITK,spinicist/ITK,biotrump/ITK,blowekamp/ITK,rhgong/itk-with-dom,CapeDrew/DCMTK-ITK,blowekamp/ITK,cpatrick/ITK-RemoteIO,richardbeare/ITK,heimdali/ITK,vfonov/ITK,PlutoniumHeart/ITK,stnava/ITK,atsnyder/ITK,msmolens/ITK,jmerkow/ITK,itkvideo/ITK,heimdali/ITK,fbudin69500/ITK,hendradarwin/ITK,spinicist/ITK,stnava/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,rhgong/itk-with-dom,zachary-williamson/ITK,itkvideo/ITK,eile/ITK,zachary-williamson/ITK,msmolens/ITK,heimdali/ITK,fuentesdt/InsightToolkit-dev,biotrump/ITK,biotrump/ITK,blowekamp/ITK,hendradarwin/ITK,spinicist/ITK,eile/ITK,jcfr/ITK,jcfr/ITK,fuentesdt/InsightToolkit-dev,hjmjohnson/ITK,zachary-williamson/ITK,atsnyder/ITK,hjmjohnson/ITK,msmolens/ITK,BlueBrain/ITK,fuentesdt/InsightToolkit-dev,CapeDrew/DCMTK-ITK,hinerm/ITK,rhgong/itk-with-dom,fbudin69500/ITK,fuentesdt/InsightToolkit-dev,LucasGandel/ITK,jcfr/ITK,zachary-williamson/ITK,hinerm/ITK,hinerm/ITK,fedral/ITK,Kitware/ITK,spinicist/ITK,CapeDrew/DCMTK-ITK,hinerm/ITK,rhgong/itk-with-dom,wkjeong/ITK,LucHermitte/ITK,InsightSoftwareConsortium/ITK,stnava/ITK,BlueBrain/ITK,paulnovo/ITK,msmolens/ITK,fedral/ITK,atsnyder/ITK,Kitware/ITK,itkvideo/ITK,hinerm/ITK,ajjl/ITK,fedral/ITK,zachary-williamson/ITK,Kitware/ITK,fbudin69500/ITK,hinerm/ITK,stnava/ITK,hendradarwin/ITK,BlueBrain/ITK,eile/ITK,wkjeong/ITK,thewtex/ITK,paulnovo/ITK,atsnyder/ITK,CapeDrew/DCMTK-ITK,malaterre/ITK,rhgong/itk-with-dom,hjmjohnson/ITK,msmolens/ITK,eile/ITK,hendradarwin/ITK,ajjl/ITK,heimdali/ITK,vfonov/ITK,InsightSoftwareConsortium/ITK,BlueBrain/ITK,eile/ITK,fedral/ITK,blowekamp/ITK,richardbeare/ITK,blowekamp/ITK,stnava/ITK,CapeDrew/DCMTK-ITK,thewtex/ITK,ajjl/ITK,malaterre/ITK,thewtex/ITK,GEHC-Surgery/ITK,spinicist/ITK,jmerkow/ITK,itkvideo/ITK,cpatrick/ITK-RemoteIO,fbudin69500/ITK,paulnovo/ITK,BRAINSia/ITK,thewtex/ITK,jmerkow/ITK,BRAINSia/ITK,heimdali/ITK,LucasGandel/ITK,paulnovo/ITK,vfonov/ITK,jcfr/ITK,msmolens/ITK,fbudin69500/ITK,richardbeare/ITK,fedral/ITK,cpatrick/ITK-RemoteIO,malaterre/ITK,spinicist/ITK,biotrump/ITK,LucHermitte/ITK,malaterre/ITK,vfonov/ITK,wkjeong/ITK,richardbeare/ITK,spinicist/ITK,rhgong/itk-with-dom,wkjeong/ITK,BlueBrain/ITK,InsightSoftwareConsortium/ITK,msmolens/ITK,stnava/ITK,biotrump/ITK,cpatrick/ITK-RemoteIO,fedral/ITK,GEHC-Surgery/ITK,heimdali/ITK,PlutoniumHeart/ITK,ajjl/ITK,ajjl/ITK,LucasGandel/ITK,BlueBrain/ITK,itkvideo/ITK,cpatrick/ITK-RemoteIO,itkvideo/ITK,CapeDrew/DCMTK-ITK,wkjeong/ITK,fuentesdt/InsightToolkit-dev,heimdali/ITK,wkjeong/ITK,malaterre/ITK,GEHC-Surgery/ITK,malaterre/ITK,atsnyder/ITK,cpatrick/ITK-RemoteIO,richardbeare/ITK,msmolens/ITK,LucHermitte/ITK,paulnovo/ITK,malaterre/ITK,cpatrick/ITK-RemoteIO,BRAINSia/ITK,hjmjohnson/ITK,jcfr/ITK,CapeDrew/DCMTK-ITK,jmerkow/ITK,vfonov/ITK,thewtex/ITK,ajjl/ITK,jcfr/ITK,LucasGandel/ITK,jcfr/ITK,stnava/ITK,hendradarwin/ITK,vfonov/ITK,vfonov/ITK,GEHC-Surgery/ITK,LucasGandel/ITK,zachary-williamson/ITK,stnava/ITK,BlueBrain/ITK,ajjl/ITK,hinerm/ITK,atsnyder/ITK,LucasGandel/ITK,cpatrick/ITK-RemoteIO,atsnyder/ITK,PlutoniumHeart/ITK,rhgong/itk-with-dom,fuentesdt/InsightToolkit-dev,CapeDrew/DCMTK-ITK,GEHC-Surgery/ITK,Kitware/ITK,Kitware/ITK,eile/ITK,fbudin69500/ITK,InsightSoftwareConsortium/ITK,BlueBrain/ITK,paulnovo/ITK,GEHC-Surgery/ITK,itkvideo/ITK,PlutoniumHeart/ITK,fuentesdt/InsightToolkit-dev,zachary-williamson/ITK,LucHermitte/ITK,hendradarwin/ITK,fedral/ITK,GEHC-Surgery/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,itkvideo/ITK,eile/ITK,hjmjohnson/ITK,rhgong/itk-with-dom,PlutoniumHeart/ITK,hendradarwin/ITK,GEHC-Surgery/ITK,hjmjohnson/ITK,blowekamp/ITK,BRAINSia/ITK,heimdali/ITK,eile/ITK,atsnyder/ITK,malaterre/ITK,biotrump/ITK,vfonov/ITK,PlutoniumHeart/ITK,LucasGandel/ITK