Messenger example - auth requests handling

Sources/XXMessengerClient/Messenger/Functions/MessengerVerifyContact.swift

+import XCTestDynamicOverlay
+import XXClient
+
+public struct MessengerVerifyContact {
+  public var run: (Contact) throws -> Bool
+
+  public func callAsFunction(_ contact: Contact) throws -> Bool {
+    try run(contact)
+  }
+}
+
+extension MessengerVerifyContact {
+  public static func live(_ env: MessengerEnvironment) -> MessengerVerifyContact {
+    MessengerVerifyContact { contact in
+      // TODO:
+      return false
+    }
+  }
+}
+
+extension MessengerVerifyContact {
+  public static let unimplemented = MessengerVerifyContact(
+    run: XCTUnimplemented("\(Self.self)")
+  )
+}