Horizontal CollectionView with paging and center content inset (Variant 1: Multiple sections)

Sample.swift

import UIKit

class CollectionCell: UICollectionViewCell {
    
    static let reuseIdentifier = "CollectionCell"
    
    static let inset = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
    
    var label: UILabel!
    
    func setup(text: String) {
        backgroundColor = UIColor.random()
        
        label = UILabel(frame: .zero)
        label.textAlignment = .center
        label.text = text
        addSubview(label)
        label.snp.makeConstraints { (make) in
            make.center.equalToSuperview()
            make.width.height.equalToSuperview()
        }
    }
}

class CollectionViewController: UIViewController {
    
    var collectionView: UICollectionView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = UIColor.white
        
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        layout.minimumLineSpacing = 0
        layout.minimumInteritemSpacing = 0
        
        collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
        collectionView.register(CollectionCell.self, forCellWithReuseIdentifier: CollectionCell.reuseIdentifier)
        collectionView.isPagingEnabled = true
        collectionView.delegate = self
        collectionView.dataSource = self
        view.addSubview(collectionView)
        
        collectionView.backgroundColor = UIColor.blue
        collectionView.snp.makeConstraints { (make) in
            make.center.equalToSuperview()
            make.leading.trailing.equalToSuperview()
            make.height.equalTo(350)
        }
    }
}

extension CollectionViewController: UICollectionViewDataSource  {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 1
    }
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 5
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: CollectionCell.reuseIdentifier, for: indexPath) as! CollectionCell
        cell.setup(text: "\(indexPath.section) -> \(indexPath.row)")
        return cell
    }
}

extension CollectionViewController: UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        sizeForItemAt indexPath: IndexPath) -> CGSize {
        let size = collectionView.frame.size
        let inset = CollectionCell.inset
        let width = size.width - inset.left - inset.right
        let height = size.height - inset.top - inset.bottom
        return CGSize(width: width, height: height)
    }
    
    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        insetForSectionAt section: Int) -> UIEdgeInsets {
        return CollectionCell.inset
    }
}

Where I can look extention snp ?

Where I can look extention snp ?

SnapKit