Trace - Heuristics for collapsing spans

[tiffon]

Add functionality for collapsing spans with various heuristics.

Some ideas:

• Collapse RPC client spans
• Collapse producer / consumer spans
• Focus on one or more service(s) (e.g. collapse non-matching, non-ancestor spans)
• Focus on some icon/demarcation (see Icon / demarcation for client spans with no responding server span #132), e.g. show errors
• Focus on the critical path

[yurishkuro]

One of the simplest to implement might be a widget that allows

• collapse all
• expand all
• expand/collapse to level 1
• expand/collapse to level 2
• ...

[felixfbecker]

+1000 for an expand all / collapse all button. Big traces are currently impossible to read

[whistlinwilly]

Would be nice to be able to "collapse outside of path" or "collapse outside subtree" - if we're looking at a span we care about, we can remove noise from the rest of the trace and focus on what we're analyzing.