All functions suddenly stopped working, time out after 5 mins, 0xE0434352 - CLR Exception

All functions in my function app stopped working. They all time out after 5 minutes. The troubleshooting chatbot in Azure shows "247 errors - 0xE0434352 - CLR Exception".

There are no errors when I view my app's logs via `/api/logstream` endpoint, except the messages that all functions have timed out.

#### Investigative information

Here's one of the hundreds of examples:

- Timestamp: 2018-11-28 05:05:58.316
- Function App version (1.0 or 2.0): 2.0
- Invocation ID:
`Executing 'Functions.myfunctionname' (Reason='Timer fired at 2018-11-28T05:05:58.3159910+00:00', Id=809ed444-d8ee-4e76-8822-620d50aa0136)`
`Timeout value of 00:05:00 exceeded by function 'Functions.myfunctionname' (Id: '809ed444-d8ee-4e76-8822-620d50aa0136'). Initiating cancellation.`
- Region: West US

#### Repro steps

I don't have the steps because the function app just stopped working some time about 12 hours ago.

#### Known workarounds

Couldn't find a workaround. Tried:
- switch to another Node.js version but it didn't help.
- pin the runtime environment to a previous version `2.0.12165.0`
- remove daily GB-s quota

Start with the reported Azure Function App version 2.0, timer invocation, five-minute timeout, and /api/logstream output. Compare the reported 0xE0434352 CLR exception with the Azure troubleshooting chatbot results; the payload names no repository files or tests. Done means identifying a reproducible cause and a verified fix or documented next step.

Written by the indexing model from the issue text.