X-Duration-Seconds header is not set on function timeout

[ewilde]

If the original function invocation takes longer than than the functions combined read_timeout and write_timeout the X-Duration-Seconds header is not set on the callback function

Expected Behaviour

X-Duration-Seconds should be set on the callback function

Steps to Reproduce (for bugs)

1. Create a function a , make is sleep for 10 seconds
2. Create a callback function b that prints the X-Duration-Seconds header
3. invoke function a i.e. curl http://127.0.0.1:8080/async-function/a -d 'hello' -H 'X-Callback-Url: http://gateway:8080/function/b'

[ewilde]

This may be expected behaviour, if it's not I guess the following high level fix:

Either

• If X-Duration-Seconds is missing from original function call response, use time measured by queue worker

Or

• Fix why header is not being set by watchdog (harder)