XXMessengerClient

Breaking changes:

• Rename Environment to NDFEnvironment.
• Update NewOrLoadUd functor parameters.

New features:

• Add XXMessengerClient library.
• Update documentation.

Sources/XXMessengerClient/Messenger/Functors/MessengerCMix.swift

-import XXClient
-import XCTestDynamicOverlay
-
-public struct MessengerCMix {
-  public var get: () -> CMix?
-  public var set: (CMix?) -> Void
-
-  public func callAsFunction() -> CMix? {
-    get()
-  }
-}
-
-extension MessengerCMix {
-  public static func live() -> MessengerCMix {
-    class Storage { var value: CMix? }
-    let storage = Storage()
-    return MessengerCMix(
-      get: { storage.value },
-      set: { storage.value = $0 }
-    )
-  }
-}
-
-extension MessengerCMix {
-  public static let unimplemented = MessengerCMix(
-    get: XCTUnimplemented("\(Self.self).get", placeholder: nil),
-    set: XCTUnimplemented("\(Self.self).set")
-  )
-}