Use @unchecked instead of nonisolated

SimpleKeychain/Accessibility.swift

@@ -1,7 +1,7 @@
 import Security
 
 /// Represents the accessibility types of Keychain items. It's a mirror of `kSecAttrAccessible` values.
-public enum Accessibility: RawRepresentable {
+public enum Accessibility: RawRepresentable, @unchecked Sendable {
 
     /// The data in the Keychain item can be accessed only while the device is unlocked by the user.
     /// See [kSecAttrAccessibleWhenUnlocked](https://developer.apple.com/documentation/security/ksecattraccessiblewhenunlocked).
@@ -50,9 +50,3 @@ public enum Accessibility: RawRepresentable {
         }
     }
 }
-
-// MARK: - Sendable conformance
-
-#if canImport(_Concurrency)
-extension Accessibility: Sendable {}
-#endif

SimpleKeychain/SimpleKeychain.swift

@@ -1,12 +1,7 @@
 import Foundation
 import Security
 #if canImport(LocalAuthentication)
-#if canImport(_Concurrency)
 @preconcurrency import LocalAuthentication
-#else
-// swiftlint:disable:next duplicate_imports
-import LocalAuthentication
-#endif
 #endif
 
 typealias RetrieveFunction = (_ query: CFDictionary, _ result: UnsafeMutablePointer<CFTypeRef?>?) -> OSStatus
@@ -15,22 +10,16 @@ typealias RemoveFunction = (_ query: CFDictionary) -> OSStatus
 /// A simple Keychain wrapper for iOS, macOS, tvOS, and watchOS.
 /// Supports sharing credentials with an **access group** or through **iCloud**, and integrating
 /// **Touch ID / Face ID**.
-public struct SimpleKeychain {
+public struct SimpleKeychain: @unchecked Sendable {
     let service: String
     let accessGroup: String?
     let accessibility: Accessibility
     let accessControlFlags: SecAccessControlCreateFlags?
     let isSynchronizable: Bool
-
-    #if canImport(_Concurrency)
-    nonisolated(unsafe) let attributes: [String: Any]
-    nonisolated(unsafe) var retrieve: RetrieveFunction = SecItemCopyMatching
-    nonisolated(unsafe) var remove: RemoveFunction = SecItemDelete
-    #else
     let attributes: [String: Any]
+
     var retrieve: RetrieveFunction = SecItemCopyMatching
     var remove: RemoveFunction = SecItemDelete
-    #endif
 
     #if canImport(LocalAuthentication) && !os(tvOS)
     let context: LAContext?
@@ -332,9 +321,3 @@ extension SimpleKeychain {
         return query
     }
 }
-
-// MARK: - Sendable conformance
-
-#if canImport(_Concurrency)
-extension SimpleKeychain: Sendable {}
-#endif