Fast way to get firstResponder

UIResponder.swift

import UIKit

private weak var _currentFirstResponder: UIResponder? = nil

extension UIResponder {
    class func mwb_firstResponder() -> UIResponder? {
        _currentFirstResponder = nil
        // If you trying send action to nil, it will automatically called on first responder
        UIApplication.shared.sendAction(#selector(mwb_findFirstResponder), to: nil, from: nil, for: nil)
        return _currentFirstResponder
    }

    @objc
    func mwb_findFirstResponder() {
        _currentFirstResponder = self
    }
}