public function column_default( $item = array(), $column_name = '' ) {

		/**
		 * Filters a string to allow plugins to add custom column content.
		 *
		 * @since 2.4.0
		 *
		 * @param string $value       Empty string.
		 * @param string $column_name Name of the column being rendered.
		 * @param array  $item        The current activity item in the loop.
		 */
		return apply_filters( 'bp_activity_admin_get_custom_column', '', $column_name, $item );
	}