feat(NODE-6245): add keepAliveInitialDelay config

[durran]

Description

Brings back the keepAliveInitialDelay option.

What is changing?

• Adds keepAliveInitialDelay as an option to pass to the socket.
• Defaults now to 120 seconds instead of 300

Is there new documentation needed for these changes?

Yes, driver docs.

What is the motivation for this change?

NODE-6245

Release Highlight

keepAliveInitialDelay may now be configured at the MongoClient level

When not present will default to 120 seconds. The option value must be specified in milliseconds.

import { MongoClient } from 'mongodb';

const client = new MongoClient(process.env.MONGODB_URI, { keepAliveInitialDelay: 100000 });

Double check the following

• Ran npm run check:lint script
• Self-review completed using the steps outlined here
• PR title follows the correct format: type(NODE-xxxx)[!]: description
  • Example: feat(NODE-1234)!: rewriting everything in coffeescript
• Changes are covered by tests
• New TODOs have a related JIRA ticket

[dariakp]

The AC on the ticket says:

allow it to be a pass-through (no validation)

do we need to revisit this requirement as a team?

[durran]

Any mongo client option has to be added to the connection string options, which is going to validate since the number is set as a uint. A negative number for this setting isn't valid anyways, so there's really no reason to set the type in the connection string module as something that can be invalid.

[dariakp]

We also have AC to add API docs and mongo manual docs for the new option - is that something we want to revisit?

[durran]

I'll update the API docs. Mongo manual I flagged on the ticket with doc changes needed.

[nbbeeken]

Capturing from our meeting: we want to get the keepAlive related options into the "options" argument we pass into tls/net .connect() and move off of calling the setKeepAlive and noDelay functions so that we are just passing Node.js configurations through to Node.js without our own validation or opinionated handling.

KeepAlive will still always be enabled and not configurable.