Introduce an annotation to mark a feature as tech preview

Annotated elements are feature-complete, but have known limitations, need bake-time or have rough angles. The API is more stable than with @experimental. Tech preview API can still be changed, but changes will be communicated.

annotation/src/main/java/io/smallrye/common/annotation/Experimental.java

@@ -9,6 +9,8 @@
 
 /**
  * Annotation that specifies that an element is experimental and may change without notice.
+ *
+ * @see TechPreview
  */
 @Inherited
 @Documented

annotation/src/main/java/io/smallrye/common/annotation/TechPreview.java

@@ -0,0 +1,31 @@
+package io.smallrye.common.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation that specifies that an element is tech preview and may change in the future.
+ * <p>
+ * Annotated elements are feature-complete, but have known limitations, need bake-time or
+ * have rough angles. The API is more stable than with {@link Experimental}.
+ * <p>
+ * Tech preview API can still be changed, but changes will be communicated.
+ *
+ * @see Experimental
+ */
+@Inherited
+@Documented
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.METHOD, ElementType.TYPE, ElementType.FIELD, ElementType.PACKAGE })
+public @interface TechPreview {
+    /**
+     * Describes why the annotated element is in tech preview.
+     *
+     * @return the tech preview description.
+     */
+    String value();
+}