LightGBM and dynamic allocation

Hello,

We are currently trying to use MMLSpark and LightGBM in our Spark cluster. We usually use default dynamic allocation of executors when starting jobs, but LightGBM seems to not work with this setting (the main Thread used to wait for executors connection only replies to the first ones created during the initialisation of the main Spark context).

How is it possible to make LightGBM work in a dynamic executors allocation way?

Thanks!

EDIT: we are using the current `master` branch