Copy stream hangs if using gzip stream compression

Hello, we caught a cool bug )

Streams work fine when copying, but if the stream is sent to the compression pipe, the entire pool of connections freezes.

Example, playback:

import postgres from 'postgres';
import { createGzip } from 'zlib';

const db = postgres({
  max: 2,
});

for (let i = 0; i < 10; i++) {
  let stream = await db
    .unsafe(`COPY pg_catalog.pg_attribute TO STDOUT`)
    .readable();

  stream.pipe(createGzip()).on('data', console.log);

  await db.unsafe(`SELECT $1 AS "CONTINUE"`, [i]);
}

console.log(await db.unsafe(`SELECT 'DONE' AS "END"`));

I play with pipe, but in any case, something is wrong with the connection pool after sending the stream to the pipe.

Reproduce the provided script with max: 2, COPY ... TO STDOUT, readable(), and createGzip(), then verify whether the following SELECT calls complete. Inspect the readable stream and connection-pool handling around COPY; done means compressed streams no longer freeze the pool and the later SELECT queries return normally.