* http: Use assert_eq in tests for better debuggability
* http: Use matches! macro instead of if let ...
* http: Simplify some bits and pieces
* http: Don't answer immediately in HTTP test server
Sometimes it can happen that we receive the response immediately
when testing the HTTP api due to kernel scheduling. Because of it, we
add a marginal 10ms async-friendly delay to minimize the risk.
* http: Use the same async runtime when testing HTTP API/worker
* http: Return a future Delay only for non-zero Duration
This allows to short-circuit in the response_wait logic and only
send/not wait for response.