- `v`: adds a tag "version" based on the expression, e.g. `v(VERSION)`
-> `t("version", VERSION)`
- `utc`: like `tm`, but converts a `DateTime<Utc>` to `i64`
automatically

this was to test cost in terms of compilation speed. doesn't seem like a
big deal but leaving it in case it is later.

- kills MeasurementWindow/WTen
- all warnings silenced
- cruft removed

t = tag,
i => int,
f => float,
s => string,
d => d128,
u => uuid,
tm => time

- no zmq socket
- uses recv_timeout so no-thrash is pretty irrelevant
- sending (with measure!) is about 1u in benches