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kotlinlang

If you look online you'll be able to find some articles about inlining and performance on the JVM, but basically one of the fundamental optimization the JVM performs is method inlining, and then it can perform some other optimizations after being able to inline methods (like escape analysis).  There are limits to how large of a method the JVM will inline or perform some optimizations on, so using the inline keyword carelessly can lead to situations where the code is slower because it makes the methods too big for the JVM to perform its runtime optimizations.