Preserve RxBox at the moment

RxSwift/RxBox.swift

@@ -8,6 +8,20 @@
 
 import Foundation
 
+// Wrapper for any value type
+public class RxBox<T> : CustomStringConvertible {
+    public let value : T
+    public init (_ value: T) {
+        self.value = value
+    }
+    
+    public var description: String {
+        get {
+            return "Box(\(self.value))"
+        }
+    }
+}
+
 // Wrapper for any value type that can be mutated
 public class RxMutableBox<T> : CustomStringConvertible {
     public var value : T