Initial implementation of channel overscroll navigation

submodules/ComponentFlow/Source/Components/Button.swift

@@ -0,0 +1,68 @@
+import Foundation
+import UIKit
+
+final class Button: CombinedComponent, Equatable {
+    let content: AnyComponent<Empty>
+    let insets: UIEdgeInsets
+    let action: () -> Void
+
+    init(
+        content: AnyComponent<Empty>,
+        insets: UIEdgeInsets,
+        action: @escaping () -> Void
+    ) {
+        self.content = content
+        self.insets = insets
+        self.action = action
+    }
+
+    static func ==(lhs: Button, rhs: Button) -> Bool {
+        if lhs.content != rhs.content {
+            return false
+        }
+        if lhs.insets != rhs.insets {
+            return false
+        }
+        return true
+    }
+
+    final class State: ComponentState {
+        var isHighlighted = false
+
+        override init() {
+            super.init()
+        }
+    }
+
+    func makeState() -> State {
+        return State()
+    }
+
+    static var body: Body {
+        let content = Child(environment: Empty.self)
+
+        return { context in
+            let content = content.update(
+                component: context.component.content,
+                availableSize: CGSize(width: context.availableSize.width, height: 44.0), transition: context.transition
+            )
+
+            let size = CGSize(width: content.size.width + context.component.insets.left + context.component.insets.right, height: content.size.height + context.component.insets.top + context.component.insets.bottom)
+
+            let component = context.component
+
+            context.add(content
+                .position(CGPoint(x: size.width / 2.0, y: size.height / 2.0))
+                .opacity(context.state.isHighlighted ? 0.2 : 1.0)
+                .update(Transition.Update { component, view, transition in
+                    view.frame = component.size.centered(around: component._position ?? CGPoint())
+                })
+                .gesture(.tap {
+                    component.action()
+                })
+            )
+            
+            return size
+        }
+    }
+}