fix(traces): update payload size after dropping traces (#1091)

## This PR

After dropping sampled-out traces, recompute `body_size`. This ensures
the `TraceAggregator`'s 3.2 MB batch limit is evaluated against only the
data that will actually be sent to the backend.

Upgrades the version of some external crates because those are the
versions used in libdatadog.

## Testing

- Unit tests

## Note
The recomputed size uses the protobuf encoded payload size, different
from the original size, computed from: (from Claude)
> - Datadog tracer path: src/traces/trace_agent.rs:506 — body_size is
the first element of the tuple returned by
get_traces_from_request_body() / get_v05_traces_from_request_body(),
which is the raw HTTP request
body byte count (msgpack-encoded bytes).
> - OTLP path: src/otlp/agent.rs:167 — let body_size =
size_of_val(&traces) where traces is a TracerPayloadCollection, giving
only the stack size of the Rust enum (~32 bytes).

The new approach be more accurate because it's computed at a later point
for the size of protobuf data, which is what's finally sent to Datadog.

By the way, the size doesn't need to be accurate. An approximate size is
good enough. See:

https://github.com/DataDog/libdatadog/blob/3f3efefb2ff45d7a5491b770480396d001b87631/libdd-trace-utils/src/send_data/mod.rs#L148

Also here are some sample logs (logging node not included in the PR)
showing the different sizes computed in different ways:
> body_size (original): 582, body_size (encoded_len): 1355
> body_size (original): 373, body_size (encoded_len): 1269
> body_size (original): 336, body_size (encoded_len): 899

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: lym953

bottlecap/Cargo.lock

@@ -44,13 +44,13 @@ rustls-pemfile = { version = "2.0", default-features = false, features = ["std"]
 rustls-pki-types = { version = "1.0", default-features = false }
 hyper-rustls = { version = "0.27.7", default-features = false }
 rand = { version = "0.8", default-features = false }
-prost = { version = "0.13", default-features = false }
-tonic-types = { version = "0.13", default-features = false }
+prost = { version = "0.14", default-features = false }
+tonic-types = { version = "0.14", default-features = false }
 zstd = { version = "0.13.3", default-features = false }
 futures = { version = "0.3.31", default-features = false }
 serde-aux = { version = "4.7", default-features = false }
 serde_html_form = { version = "0.2", default-features = false }
-opentelemetry-proto = { version = "0.30.0", features = ["trace", "with-serde", "gen-tonic"] }
+opentelemetry-proto = { version = "0.31.0", features = ["trace", "with-serde", "gen-tonic"] }
 opentelemetry-semantic-conventions = { version = "0.30", features = ["semconv_experimental"] }
 # Pinned to <0.8.3: version 0.8.3 upgraded to openssl-probe 0.2.x which scans all cert
 # directories and parses ~200 individual cert files on Lambda instead of loading a single

bottlecap/Cargo.toml

@@ -12,6 +12,8 @@ aws-lc-sys,https://github.com/aws/aws-lc-rs,ISC AND (Apache-2.0 OR ISC) AND Open
 axum,https://github.com/tokio-rs/axum,MIT,The axum Authors
 axum-core,https://github.com/tokio-rs/axum,MIT,The axum-core Authors
 base64,https://github.com/marshallpierce/rust-base64,MIT OR Apache-2.0,Marshall Pierce <marshall@mpierce.org>
+bit-set,https://github.com/contain-rs/bit-set,Apache-2.0 OR MIT,Alexis Beingessner <a.beingessner@gmail.com>
+bit-vec,https://github.com/contain-rs/bit-vec,Apache-2.0 OR MIT,Alexis Beingessner <a.beingessner@gmail.com>
 bitflags,https://github.com/bitflags/bitflags,MIT OR Apache-2.0,The Rust Project Developers
 block-buffer,https://github.com/RustCrypto/utils,MIT OR Apache-2.0,RustCrypto Developers
 buf_redux,https://github.com/abonander/buf_redux,MIT OR Apache-2.0,Austin Bonander <austin.bonander@gmail.com>
@@ -22,6 +24,7 @@ bytes,https://github.com/tokio-rs/bytes,MIT,"Carl Lerche <me@carllerche.com>, Se
 cc,https://github.com/rust-lang/cc-rs,MIT OR Apache-2.0,Alex Crichton <alex@alexcrichton.com>
 cfg-if,https://github.com/rust-lang/cfg-if,MIT OR Apache-2.0,Alex Crichton <alex@alexcrichton.com>
 chrono,https://github.com/chronotope/chrono,MIT OR Apache-2.0,The chrono Authors
+const-hex,https://github.com/danipopes/const-hex,MIT OR Apache-2.0,DaniPopes <57450786+DaniPopes@users.noreply.github.com>
 const_format,https://github.com/rodrimati1992/const_format_crates,Zlib,rodrimati1992 <rodrimatt1985@gmail.com>
 const_format_proc_macros,https://github.com/rodrimati1992/const_format_crates,Zlib,rodrimati1992 <rodrimatt1985@gmail.com>
 cookie,https://github.com/SergioBenitez/cookie-rs,MIT OR Apache-2.0,"Sergio Benitez <sb@sergio.bz>, Alex Crichton <alex@alexcrichton.com>"
@@ -144,6 +147,7 @@ powerfmt,https://github.com/jhpratt/powerfmt,MIT OR Apache-2.0,Jacob Pratt <jaco
 ppv-lite86,https://github.com/cryptocorrosion/cryptocorrosion,MIT OR Apache-2.0,The CryptoCorrosion Contributors
 proc-macro2,https://github.com/dtolnay/proc-macro2,MIT OR Apache-2.0,"David Tolnay <dtolnay@gmail.com>, Alex Crichton <alex@alexcrichton.com>"
 proc-macro2-diagnostics,https://github.com/SergioBenitez/proc-macro2-diagnostics,MIT OR Apache-2.0,Sergio Benitez <sb@sergio.bz>
+proptest,https://github.com/proptest-rs/proptest,MIT OR Apache-2.0,Jason Lingle
 prost,https://github.com/tokio-rs/prost,Apache-2.0,"Dan Burkert <dan@danburkert.com>, Lucio Franco <luciofranco14@gmail.com>, Casper Meijn <casper@meijn.net>, Tokio Contributors <team@tokio.rs>"
 prost-derive,https://github.com/tokio-rs/prost,Apache-2.0,"Dan Burkert <dan@danburkert.com>, Lucio Franco <luciofranco14@gmail.com>, Casper Meijn <casper@meijn.net>, Tokio Contributors <team@tokio.rs>"
 prost-types,https://github.com/tokio-rs/prost,Apache-2.0,"Dan Burkert <dan@danburkert.com>, Lucio Franco <luciofranco14@gmail.com>, Casper Meijn <casper@meijn.net>, Tokio Contributors <team@tokio.rs>"
@@ -158,6 +162,7 @@ r-efi,https://github.com/r-efi/r-efi,MIT OR Apache-2.0 OR LGPL-2.1-or-later,The
 rand,https://github.com/rust-random/rand,MIT OR Apache-2.0,"The Rand Project Developers, The Rust Project Developers"
 rand_chacha,https://github.com/rust-random/rand,MIT OR Apache-2.0,"The Rand Project Developers, The Rust Project Developers, The CryptoCorrosion Contributors"
 rand_core,https://github.com/rust-random/rand,MIT OR Apache-2.0,"The Rand Project Developers, The Rust Project Developers"
+rand_xorshift,https://github.com/rust-random/rngs,MIT OR Apache-2.0,"The Rand Project Developers, The Rust Project Developers"
 redox_syscall,https://gitlab.redox-os.org/redox-os/syscall,MIT,Jeremy Soller <jackpot51@gmail.com>
 regex,https://github.com/rust-lang/regex,MIT OR Apache-2.0,"The Rust Project Developers, Andrew Gallant <jamslam@gmail.com>"
 regex-automata,https://github.com/rust-lang/regex,MIT OR Apache-2.0,"The Rust Project Developers, Andrew Gallant <jamslam@gmail.com>"
@@ -174,6 +179,7 @@ rustls-native-certs,https://github.com/rustls/rustls-native-certs,Apache-2.0 OR
 rustls-pemfile,https://github.com/rustls/pemfile,Apache-2.0 OR ISC OR MIT,The rustls-pemfile Authors
 rustls-pki-types,https://github.com/rustls/pki-types,MIT OR Apache-2.0,The rustls-pki-types Authors
 rustls-webpki,https://github.com/rustls/webpki,ISC,The rustls-webpki Authors
+rusty-fork,https://github.com/altsysrq/rusty-fork,MIT OR Apache-2.0,Jason Lingle
 ryu,https://github.com/dtolnay/ryu,Apache-2.0 OR BSL-1.0,David Tolnay <dtolnay@gmail.com>
 safemem,https://github.com/abonander/safemem,MIT OR Apache-2.0,Austin Bonander <austin.bonander@gmail.com>
 schannel,https://github.com/steffengy/schannel-rs,MIT,"Steven Fackler <sfackler@gmail.com>, Steffen Butzer <steffen.butzer@outlook.com>"
@@ -224,6 +230,7 @@ tokio-rustls,https://github.com/rustls/tokio-rustls,MIT OR Apache-2.0,The tokio-
 tokio-stream,https://github.com/tokio-rs/tokio,MIT,Tokio Contributors <team@tokio.rs>
 tokio-util,https://github.com/tokio-rs/tokio,MIT,Tokio Contributors <team@tokio.rs>
 tonic,https://github.com/hyperium/tonic,MIT,Lucio Franco <luciofranco14@gmail.com>
+tonic-prost,https://github.com/hyperium/tonic,MIT,Lucio Franco <luciofranco14@gmail.com>
 tonic-types,https://github.com/hyperium/tonic,MIT,"Lucio Franco <luciofranco14@gmail.com>, Rafael Lemos <flemos.rafael.dev@gmail.com>"
 tower,https://github.com/tower-rs/tower,MIT,Tower Maintainers <team@tower-rs.com>
 tower-http,https://github.com/tower-rs/tower-http,MIT,Tower Maintainers <team@tower-rs.com>
@@ -237,6 +244,7 @@ tracing-subscriber,https://github.com/tokio-rs/tracing,MIT,"Eliza Weisman <eliza
 try-lock,https://github.com/seanmonstar/try-lock,MIT,Sean McArthur <sean@seanmonstar.com>
 twoway,https://github.com/bluss/twoway,MIT OR Apache-2.0,bluss
 typenum,https://github.com/paholg/typenum,MIT OR Apache-2.0,"Paho Lurie-Gregg <paho@paholg.com>, Andre Bogus <bogusandre@gmail.com>"
+unarray,https://github.com/cameron1024/unarray,MIT OR Apache-2.0,The unarray Authors
 uncased,https://github.com/SergioBenitez/uncased,MIT OR Apache-2.0,Sergio Benitez <sb@sergio.bz>
 unicase,https://github.com/seanmonstar/unicase,MIT OR Apache-2.0,Sean McArthur <sean@seanmonstar.com>
 unicode-ident,https://github.com/dtolnay/unicode-ident,(MIT OR Apache-2.0) AND Unicode-3.0,David Tolnay <dtolnay@gmail.com>
@@ -248,6 +256,7 @@ ustr,https://github.com/anderslanglands/ustr,BSD-2-Clause-Patent,Anders Langland
 utf8_iter,https://github.com/hsivonen/utf8_iter,Apache-2.0 OR MIT,Henri Sivonen <hsivonen@hsivonen.fi>
 valuable,https://github.com/tokio-rs/valuable,MIT,The valuable Authors
 value-bag,https://github.com/sval-rs/value-bag,Apache-2.0 OR MIT,Ashley Mannix <ashleymannix@live.com.au>
+wait-timeout,https://github.com/alexcrichton/wait-timeout,MIT OR Apache-2.0,Alex Crichton <alex@alexcrichton.com>
 want,https://github.com/seanmonstar/want,MIT,Sean McArthur <sean@seanmonstar.com>
 wasi,https://github.com/bytecodealliance/wasi,Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT,The Cranelift Project Developers
 wasip2,https://github.com/bytecodealliance/wasi-rs,Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT,The wasip2 Authors