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kotlinlang

actually I have read the source, moreover I have already observed in my app that delegates are quite costly. 

as author of the benchamark said: "I decided to use the most efficient possible equivalent implementation in Java as a baseline. This may not be totally fair to Kotlin as the two things are not the same, and delegated properties enable using patterns that are just not possible in Java." so it is quite clear that it is not exactly the same construction.

IMHO it is important and understand cost of DI. As I remember there was a problem with Guice(1) that it was useing on Android without deep knowledge and then a question "why does my app start so slow?"