add Button in Server_side processed DT

vaghig

hey guys i have a DT which data is processed in the server side using the default server_processing.php file.
how can i add a button in the last column.

this is my columns array
$columns = array(
array( 'db' => 'id', 'dt' => 0 ),
array( 'db' => 'name', 'dt' => 1 ),
array(
'db' => 'date',
'dt' => 2,
'formatter' => function( $d, $row ) {
return date( 'D, d/m/Y', strtotime($d));
}
)
);

thanks