function flush( clbk ) {
		try {
			log( line );
		} catch ( err ) {
			stream.emit( 'error', err );
		}
		line = '';
		if ( clbk ) {
			return clbk();
		}
	}
Callback to flush data to `stdout`.

@private
@param {Callback} [clbk] - callback to invoke after processing data
@returns {void}