There's no difference between the implementation for the two `count` functions of `GroupedStreamImpl`

[elenacliu]

Maybe the second count function of which declaration is public <OUT> GroupedStream<K, Integer> count(SelectAction<OUT, V> selectAction) may do count operation based on whether the key exists or not?

[ni-ze]

count(SelectAction<OUT, V> selectAction) is plan to calculate the count of the special key. But the implementation is be forgotten.

can you submit a pr to make it correct?

[elenacliu]

count(SelectAction<OUT, V> selectAction) is plan to calculate the count of the special key. But the implementation is be forgotten.

can you submit a pr to make it correct?

sure, I'll do it in the following days.