Add millisecond precision for datetime columns in Power Query in Dataflows

[richflan]

As the title suggests, the millisecond precision for datetime columns is lost in Power Query when connecting to data via a Dataflow. This is an issue when needing the data at this level of granulaity. 

This isn't the case when connecting via Power BI Desktop though, where Power Query retains the millisecond precision. 

(This was mentioned already in this post on the Forums.)  

[v-chuncz-msft]

@richflan 

You may use Time.Second to view the millisecond.