function onWrite( error ) {
		if ( error ) {
			debug( 'Encountered an error when attempting to write data to file: %s', error.message );
			throw error;
		}
		debug( 'Successfully wrote data to file: %s', file );
		COUNT += 1;
		if ( COUNT === NUM_FILES ) {
			debug( 'Successfully converted all data files.' );
			debug( 'Reading directory contents: %s', dataDir );
			readDir( dataDir, onDir2 );
		}
	}
Callback invoked after writing data to file.

@private
@param {(Error|null)} error - error object