Initial implementation of channel overscroll navigation

submodules/ComponentFlow/Source/Components/Rectangle.swift

@@ -0,0 +1,41 @@
+import Foundation
+import UIKit
+
+public final class Rectangle: Component {
+    private let color: UIColor
+    private let width: CGFloat?
+    private let height: CGFloat?
+    
+    public init(color: UIColor, width: CGFloat? = nil, height: CGFloat? = nil) {
+        self.color = color
+        self.width = width
+        self.height = height
+    }
+
+    public static func ==(lhs: Rectangle, rhs: Rectangle) -> Bool {
+        if !lhs.color.isEqual(rhs.color) {
+            return false
+        }
+        if lhs.width != rhs.width {
+            return false
+        }
+        if lhs.height != rhs.height {
+            return false
+        }
+        return true
+    }
+    
+    public func update(view: UIView, availableSize: CGSize, transition: Transition) -> CGSize {
+        var size = availableSize
+        if let width = self.width {
+            size.width = min(size.width, width)
+        }
+        if let height = self.height {
+            size.height = min(size.height, height)
+        }
+
+        view.backgroundColor = self.color
+
+        return size
+    }
+}