annotate initialize method @NotNull

common/addons/manifest-addon-loader/src/main/java/com/dfsek/terra/addons/manifest/api/MonadAddonInitializer.java

@@ -3,7 +3,12 @@ package com.dfsek.terra.addons.manifest.api;
 import com.dfsek.terra.addons.manifest.api.monad.Init;
 import com.dfsek.terra.api.util.function.monad.Monad;
 
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+
 
 public interface MonadAddonInitializer {
+    @NotNull
+    @Contract(pure = true)
     Monad<?, Init<?>> initialize();
 }

common/addons/manifest-addon-loader/src/main/java/com/dfsek/terra/addons/manifest/api/monad/Init.java

@@ -47,6 +47,10 @@ public class Init<T> implements Monad<T, Init<?>> {
         return ofPure(u);
     }
     
+    public static Monad<Void, Init<?>> unit() {
+        return Init.unit(a -> {});
+    }
+    
     public static <T> Init<T> ofPure(T t) {
         return of(Functions.constant(t));
     }