Java RestHighLevelClient missing get single task

Which is the preferred way to get a single running task by ID?
I'm looking at these two documentations (v7.9) for using Tasks:
REST API
Java Client
but i can't find a way to get a single Task through the Java client. Should i use the LowLevelClient on the task API (GET /_tasks/<task_id>) or is it better to use the HighLevelClient on the task index .index? But the index seems to contain only the completed tasks and not the running ones.

Can you check this link

I can't see anything new?! There is no option to specify a single task ID. Or what do you mean?