Implement .getExecutionInfo() and executionInfo.getQueryTrace();

[koctodox]

Add .getExecutionInfo() and executionInfo.getQueryTrace() on Alpakka Cassandra

Hi, I want to use .getExecutionInfo() and executionInfo.getQueryTrace() to trace my query execution and view Cassandra's execution plan and logical plans in my application (debug mode).

Details

I keep searching and find nothing in the documentation or on the internet. I found that DataStax has these two functions to see query tracing for debugging, but Alpakka Cassandra does not. Please add these functions and other DataStax APIs to Alpakka, specifically for streams. Thanks.