Client APIs
Export Parquet
```ts
// Create a new connection
const conn = await db.connect();

// Export Parquet
conn.send(` COPY (SELECT * FROM tbl) TO 'result-snappy.parquet' (FORMAT 'parquet');`);
const parquet_buffer = await this._db.copyFileToBuffer('result-snappy.parquet');

// Generate a download link
const link = URL.createObjectURL(new Blob([parquet_buffer]));

// Close the connection to release memory
await conn.close();
```