Marks APIs that are considered internal to Akka and may change at any point in time without any warning.
For example, this annotation should be used when the Scala
access restriction is used,
as Java has no way of representing this package restricted access and such methods and classes are represented
If a method/class annotated with this method has a javadoc/scaladoc comment, the first line MUST include
in order to be easily identifiable from generated documentation. Additional information
may be put on the same line as the INTERNAL API comment in order to clarify further.