more ios/macos targets implementation

src/iosArm64Main/kotlin/net/sergeych/synctools/ProtectedOp.iosArm64.kt

@@ -0,0 +1,27 @@
+package net.sergeych.synctools
+
+import kotlinx.atomicfu.locks.ReentrantLock
+
+/**
+ * Get the platform-depended implementation of a mutex. It does nothing in the
+ * browser and use appropriate mechanics on JVM and native targets. See
+ * [ProtectedOpImplementation.invoke], [ProtectedOpImplementation.withLock]
+ * ```kotlin
+ * val op = ProtectedOp()
+ * //...
+ * op {
+ *      // mutually exclusive execution
+ *      println("sequential execution here")
+ * }
+ * ~~~
+ */
+actual fun ProtectedOp(): ProtectedOpImplementation = object : ProtectedOpImplementation {
+    private val access = ReentrantLock()
+    override fun lock() {
+        access.lock()
+    }
+
+    override fun unlock() {
+        access.unlock()
+    }
+}