ThreadSafe.swift

final class ThreadSafe<T> {
    private var _value: T
    private let queue = DispatchQueue(label: ThreadSafe.description())
    init(_ value: T) {
        self._value = value
    }

    var value: T {
        return queue.sync { _value }
    }
  
  func atomically(_ transform: (inout T) -> ()) {
        queue.sync {
            transform(&self._value)
        }
    }
}