[iOS 레이아웃] Swift3 UICollectionView 사용법

https://sihyungyou.github.io/iOS-dequeueReusableCell/

tableview image caching | https://ios-development.tistory.com/659

&ref

Tutorial | https://www.raywenderlich.com/18895088-uicollectionview-tutorial-getting-started

ref list | https://m.blog.naver.com/magtao/220025763280

Like App Store | https://www.youtube.com/watch?v=SR7DtcT61tA

Animate | https://www.roryba.in/programming/swift/2018/03/24/animating-tables.html

Dev | https://developer.apple.com/library/archive/documentation/WindowsViews/Conceptual/CollectionViewPGforIOS/UsingtheFlowLayout/UsingtheFlowLayout.html

https://demian-develop.tistory.com/21

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