Node 16 socket issue for Legacy Restify v6

• [ x ] Searched both open and closed issues for duplicates of this issue
• [ x ] Title adequately and concisely reflects the feature or the bug

Restify Version: 6.4.0
Node.js Version: 16x

Expected behaviour

HTTP requests to the server should work

Actual behaviour

Requests don't return data

Repro case

Cause

fix: use more reliable close event
The close event from the request object is not guaranteed to fire on the
same order across major versions of Node.js, the more accurate way to
look if the connection was closed is to listen to the event on the
socket. Fixes tests on v16.
https://github.com/restify/node-restify/commit/e183e5d87435f73baa83024e937a0bcddf807757

Please backport this bugfix to the legacy 6x branch & NPM package.

Yes, 6.x is super old. But due to the major routing change discussed in https://github.com/restify/node-restify/issues/1685 I've not updated restify.

Start by reviewing the referenced commit e183e5d87435f73baa83024e937a0bcddf807757 and its corresponding code on the legacy 6.x branch. Confirm the change fixes HTTP requests that fail to return data under Node.js 16, then verify the relevant tests pass and the fix is suitable for the legacy 6.x package.