Swift SectionHeader Layout 설정

    private func createSectionHeader() -> NSCollectionLayoutBoundarySupplementaryItem {
        // Section Header Size
        let layoutSectionHeaderSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .absolute(30))
        
        // Section Header Layout
        let sectionHeader = NSCollectionLayoutBoundarySupplementaryItem(layoutSize: layoutSectionHeaderSize, elementKind: UICollectionView.elementKindSectionHeader, alignment: .top)

        return sectionHeader
    }
}