Regenerate stats payload to add is_trace_root

[ajgajg1134]

What does this PR do?

Regenerate the stats payload msgp encoder as it was missing the new is_trace_root field.

Motivation

We want is_trace_root to be available for these metrics. Eventually this code will go away with my PR here #2817, but until that PR is ready after an agent review (still a few weeks out at least) then this will resolve the problem before then.

Reviewer's Checklist

• Changed code has unit tests for its functionality at or near 100% coverage.
• System-Tests covering this feature have been added and enabled with the va.b.c-dev version tag.
• There is a benchmark for any new code, or changes to existing code.
• If this interacts with the agent in a new way, a system test has been added.
• Add an appropriate team label so this PR gets put in the right place for the release notes.
• Non-trivial go.mod changes, e.g. adding new modules, are reviewed by @DataDog/dd-trace-go-guild.

Unsure? Have a question? Request a review!

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-09-11 18:14:56

Comparing candidate commit d893820 in PR branch andrew.glaude/statsMsgp with baseline commit d1b31e8 in branch main.

Found 1 performance improvements and 7 performance regressions! Performance is the same for 50 metrics, 1 unstable metrics.

scenario:BenchmarkPartialFlushing/Disabled-24

• 🟥 execution_time [+10.209ms; +13.073ms] or [+3.779%; +4.840%]

scenario:BenchmarkPartialFlushing/Enabled-24

• 🟥 execution_time [+11.147ms; +14.022ms] or [+4.067%; +5.116%]

scenario:BenchmarkSetTagString-24

• 🟩 execution_time [-9.094ns; -6.426ns] or [-7.618%; -5.383%]

scenario:BenchmarkSingleSpanRetention/no-rules-24

• 🟥 execution_time [+9.045µs; +10.213µs] or [+3.772%; +4.259%]

scenario:BenchmarkSingleSpanRetention/with-rules/match-all-24

• 🟥 execution_time [+9.149µs; +10.775µs] or [+3.779%; +4.450%]

scenario:BenchmarkSingleSpanRetention/with-rules/match-half-24

• 🟥 execution_time [+9.482µs; +10.711µs] or [+3.924%; +4.432%]

scenario:BenchmarkStartSpan-24

• 🟥 execution_time [+93.007ns; +112.393ns] or [+4.126%; +4.986%]

scenario:BenchmarkTracerAddSpans-24

• 🟥 execution_time [+136.149ns; +173.451ns] or [+3.495%; +4.453%]

[darccio]

@ajgajg1134 I see some unrelated generated changes and I'm worried if they were missing for a long time ago or not.

[ajgajg1134]

@ajgajg1134 I see some unrelated generated changes and I'm worried if they were missing for a long time ago or not.

Yeah it appears that in addition to the new field there's also more specific error messages when a field fails to serialize. This seems fine to include here as well, do you see any other changes I'm missing?

[knusbaum]

Thanks for fixing this.

[darccio]

do you see any other changes I'm missing?

Not really, but I was surprised by all the changes. In the generator we trust.