enhancement(core): Add efficient trace payload (aka v1) encoder

[ajgajg1134]

pls no look tobz

Summary

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

How did you test this PR?

References

[pr-commenter]

Regression Detector (Agent Data Plane)

Run ID: 54a45479-295c-40d5-a9d6-7b2e2fb28b8d
Baseline: 7bb563e4 · Comparison: 1233f58a · diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment (5)

Experiments configured erratic: true are tagged (ignored) and skipped when determining which experiments regressed or improved. Experiments which are detected as erratic at runtime are tagged (erratic) to flag that the run's sample dispersion was high, but their regression / improvement signal still counts.

experiment	goal	Δ mean %	links
quality_gates_rss_dsd_medium	memory	⚪ +0.00	metrics profiles logs
quality_gates_rss_dsd_ultraheavy	memory	⚪ -0.02	metrics profiles logs
quality_gates_rss_dsd_heavy	memory	⚪ -0.14	metrics profiles logs
quality_gates_rss_idle	memory	⚪ -0.39	metrics profiles logs
quality_gates_rss_dsd_low	memory	⚪ -0.59	metrics profiles logs

Bounds Checks: ✅ Passed (5)

experiment	check	replicates	observed	links
quality_gates_rss_dsd_heavy	memory_usage	10/10	✅ 131 MiB ≤ 140 MiB	metrics profiles logs
quality_gates_rss_dsd_low	memory_usage	10/10	✅ 42.6 MiB ≤ 50 MiB	metrics profiles logs
quality_gates_rss_dsd_medium	memory_usage	10/10	✅ 64.7 MiB ≤ 75 MiB	metrics profiles logs
quality_gates_rss_dsd_ultraheavy	memory_usage	10/10	✅ 191 MiB ≤ 200 MiB	metrics profiles logs
quality_gates_rss_idle	memory_usage	10/10	✅ 28.5 MiB ≤ 40 MiB	metrics profiles logs

Explanation

A change is flagged as a regression when |Δ mean %| > 5.00% in the regressing direction for its optimization goal AND SMP marks the experiment as a regression (is_regression: true). Improvements use the matching criteria for the improving direction. Experiments configured erratic: true (tagged (ignored)) are skipped outright; experiments detected as erratic at runtime (tagged (erratic)) still count, since that flag describes sample dispersion rather than directional certainty. The Δ mean % cell is colored accordingly: 🟢 = improvement, 🔴 = regression, ⚪ = neutral. Reduction in CPU or memory is an improvement; reduction in ingress throughput is a regression.

[pr-commenter]

Binary Size Analysis (Agent Data Plane)

Baseline: 7bb563e · Comparison: 1233f58 · diff
Analysis Configuration: stripped binaries · Pass/Fail Threshold: +5%
Sizes: 40.87 MiB (baseline) vs 40.77 MiB (comparison)
Size Change: -95.36 KiB (-0.23%)

✅ Binary size difference within threshold

Changes by Module

Module	File Size	Symbols
otlp_protos::otlp_include::opentelemetry	-46.94 KiB	110
prost	+45.08 KiB	100
tokio	-41.99 KiB	707
figment	-35.41 KiB	148
serde_core	+22.35 KiB	112
core	-21.88 KiB	1545
&mut serde_json	-15.97 KiB	27
axum	-11.72 KiB	87
quick_cache	+9.63 KiB	40
saluki_components::common::datadog	+9.39 KiB	107
tonic	+8.93 KiB	51
saluki_common::cache::CacheBuilder<K,V,W,H>	-8.14 KiB	3
saluki_components::destinations::dsd_stats	+8.12 KiB	2
saluki_common::cache::Cache<K,V,W,H>	-7.52 KiB	8
piecemeal	+7.18 KiB	18
saluki_components::forwarders::cluster_agent	+7.07 KiB	6
anon.1ba911e98cbb868a3910d01d81cd64e3.695.llvm.2067643073951026959	+6.63 KiB	1
anon.261bb94b8d6de96de010fe9a3c608bbb.4.llvm.7628180700126258038	-6.63 KiB	1
saluki_components::transforms::trace_sampler	-6.60 KiB	11
saluki_components::sources::otlp	+6.21 KiB	21

Detailed Symbol Changes

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +189% +19.7Ki  +191% +19.7Ki    saluki_components::encoders::datadog::metrics::encode_v3_metrics_batch::h183af91d6a7ed4a5
 +36e2% +17.6Ki +42e2% +17.6Ki    prost::message::Message::encode::h033f747c7fcca8bd
 +26e2% +13.8Ki +44e2% +13.8Ki    _<saluki_components::transforms::trace_obfuscation::TraceObfuscation as saluki_core::components::transforms::SynchronousTransform>::transform_buffer::h8a1ac133c92b7e0f
  [NEW] +13.3Ki  [NEW] +13.1Ki    saluki_components::common::datadog::apm::_::_<impl serde_core::de::Deserialize for saluki_components::common::datadog::apm::ApmConfiguration>::deserialize::h81d7f8a7cda2edc6
 +20e2% +12.7Ki +22e2% +12.7Ki    prost::message::Message::encode_to_vec::hb5ea4dcf442722e6
  +624% +11.7Ki  +691% +11.7Ki    _<saluki_components::sources::otlp::logs::translator::OtlpLogsTranslator as core::iter::traits::iterator::Iterator>::next::h2d6fd7f0b3ed8983
  [NEW] +9.02Ki  [NEW] +8.87Ki    _<serde_json::de::SeqAccess<R> as serde_core::de::SeqAccess>::next_element_seed::h04599995f9f7becf
  [NEW] +8.23Ki  [NEW] +8.09Ki    _<tracing::instrument::Instrumented<T> as core::future::future::Future>::poll::h6650231af0cdb8f5
  [NEW] +7.99Ki  [NEW] +7.81Ki    _<saluki_components::destinations::dsd_stats::DogStatsDStatsAPIHandler as saluki_api::APIHandler>::generate_routes::h166352a1b6d1824d
  [NEW] +7.57Ki  [NEW] +7.37Ki    _<saluki_components::encoders::datadog::traces::DatadogTrace as saluki_core::components::encoders::Encoder>::run::_{{closure}}::hb6e71c7eb3e17af9
  [NEW] +7.51Ki  [NEW] +7.36Ki    _<core::marker::PhantomData<T> as serde_core::de::DeserializeSeed>::deserialize::h3674312e8f38a035
  [DEL] -7.36Ki  [DEL] -7.20Ki    _<&mut serde_json::de::Deserializer<R> as serde_core::de::Deserializer>::deserialize_struct::h4d04809f2fddc209
  [DEL] -7.57Ki  [DEL] -7.37Ki    _<saluki_components::encoders::datadog::traces::DatadogTrace as saluki_core::components::encoders::Encoder>::run::_{{closure}}::h1889b8e699e3b054
  [DEL] -7.77Ki  [DEL] -7.62Ki    _<tracing::instrument::Instrumented<T> as core::future::future::Future>::poll::h7a3f66a8ac330560
  [DEL] -8.02Ki  [DEL] -7.86Ki    _<&mut serde_json::de::Deserializer<R> as serde_core::de::Deserializer>::deserialize_struct::hca5756677c477512
  [DEL] -9.87Ki  [DEL] -9.70Ki    _<&mut serde_json::de::Deserializer<R> as serde_core::de::Deserializer>::deserialize_struct::he770aa8f5094e2d9
  [DEL] -12.1Ki  [DEL] -12.0Ki    saluki_components::sources::otlp::logs::transform::transform_log_record::hea2a036923af6631
  [DEL] -14.1Ki  [DEL] -14.0Ki    saluki_components::transforms::trace_obfuscation::TraceObfuscation::obfuscate_span::h9eaa4de856be9025
  [DEL] -14.8Ki  [DEL] -14.7Ki    figment::figment::Figment::extract::h962b28a07c04a29f
 -71.9% -15.4Ki -72.2% -15.4Ki    h2::proto::connection::DynConnection<B>::recv_frame::h2860dcc6f1c3655c
  -1.5%  -127Ki  -0.6% -38.6Ki    [9497 Others]
  -0.2% -95.4Ki  -0.0% -6.42Ki    TOTAL