The metadata for a focusable Grid row. Focusable rows include
headers, group headers and footers, and data rows.

cells NavigationCell[]

An array of focusable cells which are associated with this row.

dataItem any

The data item for this row.

dataRowIndex number

The data item index for this row.

index number

The index of the focusable row. The row index is absolute and
does not change with paging. Typically, the first header row is at index 0.