feat: Renderer::render_to(impl Write, ..)

[aatifsyed]

No description provided.

[epage]

What is the motivation for this new API?

btw we've found it best if these things are discussed in issues first to ensure alignment (and other benefits) before moving on to implementation. Looks like we don't call that out in a CONTRIBUTING.md. @Muscraft I leave it to you whether you want my standard boileplate, write your own guide, or to leave it.

[aatifsyed]

I'm building reporting for my application, and don't want to allocate intermediate strings :)

I understand that there's StyledBuffer already, but that's a deeper refactor that I'm not interested in writing at this time :)

[epage]

I'm building reporting for my application, and don't want to allocate intermediate strings :)

So this is for performance? Did profiling show that this was a hotspot?

[aatifsyed]

So this is for performance? Did profiling show that this was a hotspot?

No and no, the following just felt wrong :) :

impl fmt::Display for MyError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // ...
        let s = my_renderer.render(my_report);
        f.write_str(&s)
    }
}