GH-919 - Add @CheckReturnValue and use it in Scenario API.

spring-modulith-core/src/main/java/org/springframework/modulith/core/util/CheckReturnValue.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.modulith.core.util;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Findbugs and IDEA handle any annotation with name "CheckReturnValue" in return value check.
+ *
+ * @see <a href=
+ *      "https://github.com/findbugsproject/findbugs/blob/264ae7baf890d2b347d91805c90057062b5dcb1e/findbugs/src/java/edu/umd/cs/findbugs/detect/BuildCheckReturnAnnotationDatabase.java#L120">Findbugs
+ *      source code</a>
+ * @since 1.3
+ */
+@Target({
+		ElementType.CONSTRUCTOR,
+		ElementType.METHOD,
+		ElementType.PACKAGE,
+		ElementType.TYPE,
+})
+@Retention(RetentionPolicy.CLASS)
+public @interface CheckReturnValue {}