Fixes https://emqx.atlassian.net/browse/EMQX-9099
The default value for `request_timeout` is 15 seconds, and the default
resume interval is also 15 seconds (the health check timeout, if
`resume_interval` is not explicitly given). This means that, in
practice, if a buffer worker ever gets into the blocked state, then
almost all requests will timeout.
Proposed improvement:
- `request_timeout` should by default be twice as much as
health_check_interval.
- Emit a alarm if `request_timeout` is not greater than
`health_check_interval`.
20414d7373