How to use BehaviorRelay as an alternate to Variable in RxSwift?

Question

As of RxSwift4, Variable is moved to Deprecated.swift marking the possible deprecation of Variable in future. An alternate proposed to

Answer 1

AshKan answer is great but I came here looking for a missing method from the solution. Append:

extension BehaviorRelay where Element: RangeReplaceableCollection {
        
    func append(_ subElement: Element.Element) {
        var newValue = value
        newValue.append(subElement)
        accept(newValue)
    }
}