The initial feed will download with 4 post for previewing, but if the user scrolling down then load more posts, so i need to add section to the bottom table view and section remove from the top.

Jerky Scrolling TableView After insert Sectionsng Section

import UIKit

//import XCGLogger

typealias CheckResult = (Bool)->()


class NewsViewController: BaseViewController {
    
    let newsfeedCellId = "newsfeedCellId"
    
    // inject  object dependency
    lazy var apiClient: APINewsFeedsProtocol =  APINewsFeedWebClient()
    var tableViewIndex : IndexPath?
    var states : [[State]]?
    
    // variable to save the last position visited, default to zero
    fileprivate var lastContentOffset: CGFloat = 0
     //variable to save the  section added from top
    var sectionFromTop : Int?
    //variable to save the  section added from bottom
    var sectionFromBottom  : Int?
    var newestStateTime : Date?
    var oldestStateTime : Date?
    
    
    var searchBar : LeftAlignedSearchBar!
    override func viewDidLoad() {
        self.registerViews()
        self.setupViews()
        self.loadDataToTheView()
        states = [[State]]()

        initUpdateUI(createdAfter: nil, createdBefore: nil, completion: nil)
    }

    
    lazy  var newsFeedTableView : UITableView = {
        var tableView = UITableView()
        tableView.backgroundColor = UIColor.white
        tableView.dataSource = self
        tableView.separatorStyle = .none
        tableView.delegate = self
        tableView.translatesAutoresizingMaskIntoConstraints = false
        return tableView
    }()
}

extension NewsViewController  {
    
    override func setupViews() {
        self.view.addSubview(newsFeedTableView)
        self.newsFeedTableView.fillSuperview()//rander the full screen
    }
    
    override func registerViews() {
        newsFeedTableView.register(NewsTableViewViewCell.self, forCellReuseIdentifier: newsfeedCellId)
    }
}


extension NewsViewController : UITableViewDataSource{
    func numberOfSections(in tableView: UITableView) -> Int {
        return states?.count ?? 0
    }
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return states?[section].count ?? 0
    }
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        
        let  _states = self.states?[indexPath.section]
        let  _state = _states?[indexPath.row]
        
        //let's get an estimation of the height of our cell based on user.bioText
        let approximateWidthOfStateTextView = view.frame.width  - 10
        
        return 250 + (_state?.text.height(withConstrainedWidth: approximateWidthOfStateTextView, font: UIFont(name: Constants.FontNames.SFNSText.SFNSTextRegular, size: 14)!))!
    }
    
    
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        guard let indexpath = tableViewIndex else { return }
        if self.lastContentOffset > scrollView.contentOffset.y {
            if let _states   =   states?[indexpath.section]{
                if _states.count / 2 == indexpath.row + 1  {
                    if sectionFromTop != indexpath.section {
                        sectionFromTop = indexpath.section
                        self.newestState(createdAfter: _states.first?.createdAt, completion: nil)
                    }
                }
            }
        } else if self.lastContentOffset < scrollView.contentOffset.y  {
            
            if let _states   =   states?[indexpath.section]{
                if _states.count / 2 == indexpath.row + 1 {
                    if sectionFromBottom != indexpath.section {
                        sectionFromBottom = indexpath.section
                        self.oldestState(createdBefore: _states.last?.createdAt, completion: nil)
                    }
                }
            }
        }
        self.lastContentOffset = scrollView.contentOffset.y
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: newsfeedCellId, for: indexPath) as! NewsTableViewViewCell
        
           if let  _states = states?[indexPath.section]{
            tableViewIndex = indexPath
            cell.state = _states[indexPath.row]
            cell.backgroundColor = UIColor.blue
        }
        return cell
    }
    
}

extension NewsViewController : UITableViewDelegate {
    
}

//MARK:- Load Data to the UI
extension NewsViewController  {
    
    func initUpdateUI(createdAfter: Date?, createdBefore: Date?, completion: CheckResult?){
        
        self.loadNewsFeeds(createdAfter: nil, createdBefore: nil, completion: {(states) in
            if let sortedStates = states {
                self.states?.append(sortedStates) //Update states property
                self.newestStateTime = sortedStates.first?.createdAt
                self.oldestStateTime = sortedStates.last?.createdAt
                DispatchQueue.main.async{
                    self.newsFeedTableView.reloadData()
                    completion?(true)
                }
            }
        } )
    }
    
    func newestState(createdAfter createdAt: Date?, completion :  CheckResult?){
        self.loadNewsFeeds(createdAfter: createdAt, createdBefore: nil, completion: {(states) in
            if let sortedStates = states {
                guard let firstCreatedAt = sortedStates.first?.createdAt else {
                    completion?(false)
                    return
                }
                guard   let _newestStateTime = self.newestStateTime  ,   _newestStateTime <  firstCreatedAt else {
                    completion?(false)
                    return
                }
                self.newestStateTime = firstCreatedAt
                self.states?.appendAtBeginning(newItem: sortedStates)
                self.newsFeedTableView.insertSections([(self.states?.count)! - 3], with: UITableViewRowAnimation.none)
                if (self.states?.count)! > 3 {
                    self.states?.removeLast()
                    let statesForoldestStateTime = self.states?.last
                    self.oldestStateTime = statesForoldestStateTime?.last?.createdAt
                    self.newsFeedTableView.deleteSections([(self.states?.count)! - 1], with: UITableViewRowAnimation.none)
                }
                completion?(true)
                return
            }
        } )
    }
    
    func oldestState(createdBefore createdAt: Date?, completion :  CheckResult? ){
        self.loadNewsFeeds(createdAfter: nil, createdBefore: createdAt, completion: {(states) in
            if let sortedStates = states {
                guard let  lastCreatedAt  =  sortedStates.last?.createdAt else {
                    completion?(false)
                    return
                }
                guard   let _oldestStateTime = self.oldestStateTime  ,  _oldestStateTime >  lastCreatedAt else {
                    completion?(false)
                    return
                }
                self.oldestStateTime = lastCreatedAt
                self.states?.append(sortedStates) //Update state  property
                self.newsFeedTableView.insertSections([(self.states?.count)! - 1], with: .none)
                if (self.states?.count)! > 3 {
                    self.states?.removeFirst()
                    let statesForoldestStateTime = self.states?.first
                    self.newestStateTime = statesForoldestStateTime?.first?.createdAt
                    let indexpostion = (self.states?.count)! - 3
                    self.newsFeedTableView.deleteSections([indexpostion], with: UITableViewRowAnimation.none)
                }
                completion?(true)
                return
            }
        } )
    }
    
    private func loadNewsFeeds(createdAfter: Date?, createdBefore: Date?, completion: @escaping ([State]?)
        -> ()) {
        
        var friendScopeId : UUID?
        for (key , value) in (Global.account?.scopesDict)!{
            if key == "friends" { friendScopeId = value.id }
        }
        
        guard let _friendScopeId =  friendScopeId else { return }
        
        let statesByScope = StatesByScope(scopeId: String(describing: _friendScopeId), start: 0, limit: 0, createdAfter: createdAfter, createdBefore: createdBefore)
        apiClient.loadNewsFeeds(forScope: statesByScope, completion: {(states, serviceError) in
            if let error = serviceError {
                print(error.localizedDescription) //Handle service error
            } else if let _states = states {
                let sortedStates = _states.sorted(by: {$0.createdAt! > $1.createdAt!})
                completion(sortedStates)
            }
        } )
    }
    
}

class NewsTableViewViewCell : BaseTableViewCell{
    
      var state : State?{
        didSet{
            statesTextView.text = state?.text
        }
    }

    lazy var  statesTextView: UITextView = {
        let textView = UITextView()
        textView.translatesAutoresizingMaskIntoConstraints = false
        return textView
    }()
    
    override func setupViews() {
        super.setupViews()
        addSubview(statesTextView)
            statesTextView.anchor(self.topAnchor, left:  self.leftAnchor, bottom: self.bottomAnchor, right: self.rightAnchor, topConstant: 5, leftConstant: 10, bottomConstant: 2, rightConstant: 5, widthConstant: 0, heightConstant: 0)
    }
}