feat: 🎸 monotonic and realTime lambdas in Clock class

src/main/java/vertx/effect/Clock.java

@@ -0,0 +1,24 @@
+package vertx.effect;
+
+import vertx.effect.exp.Cons;
+
+import java.time.Duration;
+import java.util.concurrent.TimeUnit;
+
+public final class Clock {
+
+    private Clock(){}
+
+    public static λ<Void,Long> monotonic = v -> Cons.success(System.nanoTime());
+
+    public static λ<Void,Long> realTime = v -> Cons.success(System.currentTimeMillis());
+
+    public static λ<Void,Long> monotonic(TimeUnit unit){
+        return v -> monotonic.apply(null).map( time -> unit.convert(Duration.ofNanos(time)));
+    }
+
+    public static λ<Void,Long> realTime(TimeUnit unit){
+        return v -> realTime.apply(null).map( time -> unit.convert(Duration.ofMillis(time)));
+    }
+
+}