public function __construct( $file, $params = array() ) {
		$default_args = array(
			'start_pos'        => 0, // File pointer start.
			'end_pos'          => -1, // File pointer end.
			'lines'            => -1, // Max lines to read.
			'mapping'          => array(), // Column mapping. csv_heading => schema_heading.
			'parse'            => false, // Whether to sanitize and format data.
			'update_existing'  => false, // Whether to update existing items.
			'delimiter'        => ',', // CSV delimiter.
			'prevent_timeouts' => true, // Check memory and time usage and abort if reaching limit.
			'enclosure'        => '"', // The character used to wrap text in the CSV.
			'escape'           => "\0", // PHP uses '\' as the default escape character. This is not RFC-4180 compliant. This disables the escape character.
		);

		$this->params = wp_parse_args( $params, $default_args );
		$this->file   = $file;

		if ( isset( $this->params['mapping']['from'], $this->params['mapping']['to'] ) ) {
			$this->params['mapping'] = array_combine( $this->params['mapping']['from'], $this->params['mapping']['to'] );
		}

		// Import mappings for CSV data.
		include_once dirname( dirname( __FILE__ ) ) . '/admin/importers/mappings/mappings.php';

		$this->read_file();
	}