当浏览Kotlin的stdlib时，I often see the @InlineOnly注释.据我回忆，注释恰好只在inline个函数上.这个注释的目的是什么？inline个函数总是内联的，这不是很明显吗？它的文档并没有真正的帮助
Specifies that this function should not be called directly without inlining
Is it possible for inline functions to be called not inline?
引用here的答案:
InlineOnly means that the Java method corresponding to this Kotlin function is marked private so that Java code can not access it (which is the only way to call an inline function without actually inlining it).
此注释为internal只是因为
This annotation was added in the last moment before release, so we hadn't time to validate the design and decided to keep it internal for a while. There are good chances we make it public later.