Add parameter --maxConcurrency to prevent different load errors.

[tilmanschweitzer]

Add parameter --maxConcurrency to prevent different load errors.

Depending on the content different load errors like 'Bandwidth exhausted'
or 'Received RST_STREAM with code 2' occur and cause the import to be incomplete.
Limiting the concurrent imported batches seems to prevents issues.
The default behaviour is still without any limit.

see #411

[nonoumasy]

does this fix the bandwidth exhausted issue?

[tilmanschweitzer]

@nonoumasy A max concurrency of 45 worked for my use case. Around a concurrency of 48 the issue started again. But I don't know if there are other aspects that contribute to the issue.

[nonoumasy]

@nonoumasy A max concurrency of 45 worked for my use case. Around a concurrency of 48 the issue started again. But I don't know if there are other aspects that contribute to the issue.

Thanks @tilmanschweitzer.
btw how do I use this parameter?
Do I just do something like?

npx -p node-firestore-import-export firestore-import -a credentials.json -b -maxConcurrency=45 backup.json

Also, when you get this issue after importing, is there possible data loss(some data doesn't get imported into firestore)? is data corruption a possibility?