fix(NODE-3810): delay timeout errors by one event loop tick

[nbbeeken]

Description

What is changing?

Delay timeout errors from a socket by one event loop tick.

What is the motivation for this change?

In FAAS environments timers will expire between invocations but will only execute upon waking up. Node.js always runs timeouts first in the event loop, this means our monitoring socket will give us a timeout error before it reads the already pending hello response. By putting the timeout error logic inside another (small as possible) timeout callback it will enforce timeout errors to be handled on the next event loop iteration, giving the driver the opportunity to first read from the socket. If it is able to read, it will clear the timeout preventing the error from being raised to our monitoring logic. If nothing is ready pending to be read from the socket, the (small as possible) timeout will fire making the timeout error occur as usual.

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>
• Changes are covered by tests
• New TODOs have a related JIRA ticket

[durran]

LGTM if we're ok with my one question. Nice work.

[dariakp]

agree with Bailey's suggestion but otherwise LGTM