Fix. NPE on ActorRef

Author: sleipnir

src/main/java/io/eigr/spawn/api/InvocationOpts.java

@@ -15,11 +15,14 @@
 @NoArgsConstructor
 public class InvocationOpts {
 
-    private boolean async;
+    @Builder.Default
+    private boolean async = false;
 
-    private Optional<Long> delay;
+    @Builder.Default
+    private Optional<Long> delay = Optional.empty();
 
-    private Optional<LocalDateTime> scheduledTo;
+    @Builder.Default
+    private Optional<LocalDateTime> scheduledTo = Optional.empty();
 
     public long getScheduleTimeInLong() {
         if (scheduledTo.isPresent()) {