FileStreamDisconnectUploadError when checking file validity
Hello,

# The problem

I have a problem when checking for the validity of the files sent by multipart request from the client side.

The client sends a multipart request with maximum 5 different files, then the server loops through them to check if every file is an instance of `stream.Readable`. While looping through the files an error occures: `FileStreamDisconnectUploadError: Request disconnected during file upload stream parsing.`.

The first file is checked but then the others files are never read.

This is what my loop looks like:

```
for (const pic of data.pictures) {
      const resolved = await pic;
      if (!(resolved.stream instanceof stream.Readable)) return new Error('Wrong file');
}
```

The error is raised when executing the line `const resolved = await pic;`.
The first file fills the `resolved` variable but it never gets filled again with the next files.

# What I tried

- I tried to destroy the stream after the check: `resolved.stream.destroy();`
- I tried to replace the `for...of` loop with a `map`

# Some thoughts

Before making the requests by the client, I sent the requests using curl according to these [examples](https://github.com/jaydenseric/graphql-multipart-request-spec). But the error still occured.

I work on a Macbook with MacOS Sierra 10.12.6 and curl 7.54.0 which uses `SecureTransport`, as it is the native TLS library.

What is interesting is that my coworkers, which work with the same Macbook as mine but with MacOS High Sierra and curl 7.54.0 which uses `LibreSSL` as TLS library, manage to get the requests work with the server. Of course we tried with the exact same requests and on a server running on my mac.


Do you have any idea why the error occures and why does the `await pic` never manage to complete ?

Thanks for your time.