sunburst layout toggle

[brendangregg]

Similar to #8, this would be an option to draw the flamegraphs in the sunburst layout (radial coordinates).

First use of it I think came from here by @paulirish: https://bugs.chromium.org/p/chromium/issues/detail?id=452624

I've also written about the layout here: http://www.brendangregg.com/blog/2017-02-06/flamegraphs-vs-treemaps-vs-sunburst.html

We can have it as a mode. This is why I wanted flamegraphs to go d3 in the first place, so we can make it more interactive and manipulatable.

[nhick]

Found this recent implementation that might help getting started: https://bl.ocks.org/kerryrodden/7090426
Happy to give it a go later this week unless someone beats me to it.

[paulirish]

TBH, I'm much less fond of the sunburst than I used to be.

The general challenge with flamegraphs is focusing their user's attention on the wide&flat parts and ignoring spiky flames. I feel like the sunburst draws attention to the spikes even more than the typical flamegraph layout.

Of course it could always be interesting to toggle to sunburst, but I wouldn't necessarily encourage it these days. :) I think flame and icicle views are the bees knees.

IMO if sunburst were attempted, I think it definitely needs the adjacent tree (like we see in Baobab).