Consider adding #[must_use] to MetricBuilder

[robinst]

I just updated my code to make use of tags (thanks for adding it, works great!). Now I have this code for example:

client.mark_with_tags("metric")
    .with_tag("key", "value")
    .send()
    .ok();

One thing that came up in the review was that it's easy to forget to call .send() on the MetricBuilder. And if you do, there's no warning.

So I was wondering, have you considered annotating MetricBuilder with #[must_use]? I gave it a quick try locally and it seems to work nicely, it results in a warning like this:

warning: unused cadence::builder::MetricBuilder which must be used

It prints that warning if you just have a mark_with_tags(...) and even when you have mark_with_tags(...).with_tag(...) (but forgot send).

[56quarters]

Great catch! I'll add this soon

[robinst]

That was quick :). Thanks!

While we have the example in the description, have you considered adding an alternative to the send method that ignores any errors instead of returning a result? Currently, not calling .ok() on the Result results in a warning.

[56quarters]

That method could be added. What do you think a good name would be? send_quiet()?

[56quarters]

I've opened #65 for the method that ignores the results and doesn't require calling .ok() on the result of .send()