fix(NODE-6600): set object mode for message chunking correctly

[addaleax]

Description

What is changing?

Is there new documentation needed for these changes?

What is the motivation for this change?

We're now aligning with the Node.js streams API contract.

Release Highlight

Socket read stream set to object mode

Socket data was being read with a stream set to buffer mode when it should be set to object mode to prevent inaccurate data chunking, which may have caused message parsing errors in rare cases.

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

[nbbeeken]

What are the release notes for this?

[addaleax]

@nbbeeken Do you think this is worth calling out in release notes?

[nbbeeken]

Yes even if it is just a sentence that points to what is being corrected without elaborating in detail we should inform what folks may have faced if this is a bug that could have occurred on this or prior versions. The versions that have this correctness issue may be in use for years and we'll want a guide that describes in human terms what the problem was as a reference.

I think this could work if it sounds accurate to you:

Socket read stream set to object mode

Socket data was being read with a stream set to buffer mode when it should be set to object mode to prevent inaccurate data chunking, which may have caused message parsing errors in rare cases.

[addaleax]

@nbbeeken Sure, that works for me 🙂