How can I get current row on "onMoveStart" event?

I want to change the UI (not just style of the row) of the row when the row has start moving.
I wanted the current row index or key to know that which row has started to move.

The issue names only the onMoveStart event and the desired row index or key; begin by locating that event's implementation and tracing the row data available when movement starts. Done means the event provides enough information to identify the row so the UI can react to it.

Written by the indexing model from the issue text.