kotlin sample

[loganj]

To flush out any kotlin-unfriendly API.

This will likely drive a kotlin extensions module as well.

[Lakedaemon]

I'm currently evaluating flow 1.00 alpha 2 in a kotlin project. So far, converting java to kotlin in intellij with the java samples provided is working fine... It shouldn't be a lot of work to write a kotlin Sample (you have to be carefull about Nullable and notNullable java types in method signatures though).