Add NSOLID_CONT_CPU_PROFILE environment variable support.
Add NSOLID_CONT_CPU_PROFILE_INTERVAL environment variable support.
Implement contCpuProfile and contCpuProfileInterval config options.
Set default interval to 30000ms (30 seconds).
Update initializeConfig and updateConfig functions.

PR-URL: #282
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Create and initialize ContinuousProfiler in EnvList.
Add configuration handling for continuous profiling options.
Update EnvList to enable/disable profiling based on config.
Add proper cleanup in shutdown sequence.
Expose ContinuousProfiler through GetContinuousProfiler() method.

PR-URL: #282
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Add test-nsolid-config-continuous-profiling.js for API configuration.
Add test-nsolid-config-continuous-profiling-env.js for environment
variables.

PR-URL: #282
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Add ExportContinuousProfile RPC to nsolid_service.proto.
Add start_ts and end_ts fields to Asset message.

PR-URL: #282
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Add AssetStreamRpcType enum to differentiate between RPC types.
Modify AssetStream constructor to accept RPC type parameter.
Update Write method to support both ExportAsset and
ExportContinuousProfile.
Add safety assertion for WritesDone method.

PR-URL: #282
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Add continuous profiler callback and queue.
Register hook with ContinuousProfiler during agent startup.
Implement got_continuous_profile method for handling profile data.
Add conflict resolution between manual and continuous profiling.
Update profile timestamp handling for better accuracy.
Add proper cleanup in shutdown sequence.

PR-URL: #282
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Add test-grpc-continuous-profile.mjs for testing continuous profiling.
Update gRPC agent server test fixture.
Test profile data transmission and format.
Verify continuous profiling configuration options.
Please enter the commit message for your changes. Lines starting.

PR-URL: #282
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

PR-URL: #302
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Fixes: nodesource/nsolid-roadmap#30
Signed-off-by: Juan José Arboleda <soyjuanarbol@gmail.com>
PR-URL: #297
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

PR-URL: #290
Refs: nodesource/ebpf-roadmap#1
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

PR-URL: #307
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

PR-URL: #308
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

Fixes: nodesource/nsolid-roadmap#31
PR-URL: #309
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

Add state tracking to prevent excessive `uv_async_t::send()` calls.

Benchmark results for (40k and 50k):

```
=== Benchmark Summary ===

Benchmark Type: wrk2
Old Version: ./nsolid_baseline
New Version: ./nsolid_span_collector
Iterations: 50
Connections: 10
Duration: 60s
Rate: 40k

=== Latency Percentile Distribution ===

+------------+------------------+------------------+------------+---------+--------------+
| Percentile | Old Version (ms) | New Version (ms) | Difference | p-value | Significance |
+------------+------------------+------------------+------------+---------+--------------+
| P50        | 1.09             | 1.10             | +0.40%     | 0.00    | ***          |
| P75        | 1.67             | 1.67             | +0.03%     | 0.73    |              |
| P90        | 2.22             | 2.22             | -0.23%     | 0.01    | **           |
| P95        | 2.54             | 2.53             | -0.52%     | 0.00    | ***          |
| P99        | 3.16             | 3.10             | -1.82%     | 0.00    | ***          |
| P99.9      | 4.98             | 4.36             | -12.45%    | 0.01    | ***          |
| P99.99     | 9.97             | 8.96             | -10.09%    | 0.13    |              |
| P99.999    | 12.91            | 11.77            | -8.88%     | 0.15    |              |
+------------+------------------+------------------+------------+---------+--------------+
```

```
=== Benchmark Summary ===

Benchmark Type: wrk2
Old Version: ./nsolid_baseline
New Version: ./nsolid_span_collector
Iterations: 50
Connections: 10
Duration: 60s
Rate: 50k

=== Latency Percentile Distribution ===

+------------+------------------+------------------+------------+---------+--------------+
| Percentile | Old Version (ms) | New Version (ms) | Difference | p-value | Significance |
+------------+------------------+------------------+------------+---------+--------------+
| P50        | 0.98             | 0.95             | -3.76%     | 0.16    |              |
| P75        | 1.78             | 1.54             | -13.31%    | 0.23    |              |
| P90        | 3.36             | 2.49             | -25.71%    | 0.18    |              |
| P95        | 5.37             | 3.51             | -34.60%    | 0.09    | *            |
| P99        | 18.08            | 10.66            | -41.02%    | 0.01    | ***          |
| P99.9      | 50.91            | 30.78            | -39.54%    | 0.01    | ***          |
| P99.99     | 72.19            | 47.71            | -33.91%    | 0.01    | ***          |
| P99.999    | 75.98            | 51.69            | -31.97%    | 0.01    | ***          |
+------------+------------------+------------------+------------+---------+--------------+

```
TL;DR

The new version demonstrates a clear improvement in latency
performance, particularly for edge cases and high-load scenarios
represented by the tail latencies. This suggests better handling of
resource-intensive operations or improved performance under stress
conditions.

PR-URL: #287
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: dobleuber <wbertc@gmail.com>

PR-URL: #322
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

PR-URL: #180
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-by: Trevor Norris <trev.norris@gmail.com>
PR-URL: #322

This is a major dependency update that includes:

* Update Protocol Buffers (protobuf) from previous version to 30.2
* Update gRPC from previous version to 1.72.0
* Add new build targets in protobuf.gyp:
  - protoc: Protocol Buffer compiler executable
  - protoc-gen-cpp: C++ code generator plugin for protoc

Infrastructure improvements:
* Add helper functions in tools/dep_updaters/utils.sh:
  - setup_protoc_environment: Configure protoc build environment
  - regenerate_proto_otel: Regenerate OpenTelemetry proto files
  - regenerate_proto_agents: Regenerate NSolid agent proto files

* Enhance updater scripts:
  - update-protobuf.sh: Improved handling of abseil-cpp dependency
  - update-grpc.sh: Streamlined update process
  - update-opentelemetry-cpp.sh: Automated proto regeneration

* Regenerate all proto files in agents/grpc/src/proto/ with updated
  protoc:
  - Updated *.pb.cc, *.pb.h, and *.grpc.pb.h files
  - Ensures compatibility with new protobuf/gRPC versions

This update ensures NSolid remains compatible with the latest protocol
buffer and gRPC implementations, improving performance and security.

PR-URL: #303
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Enable AsyncTSQueue to accept both single-element (T&&, const T&) and
batch (std::vector<T>&&, const std::vector<T>&) callbacks, using
if constexpr with type traits for compile-time dispatch. Ensure correct
argument forwarding and update tests to cover all supported callback
signatures.

PR-URL: #312
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

Only call async_handle_->send() when the queue transitions from empty to
non-empty (size == 1). This reduces unnecessary async wakeups and
improves performance in high-throughput scenarios.
On top of that DRY enqueue logic.

PR-URL: #318
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

Introduce AsyncTSQueueOptions for batching: notification is sent when
the queue size reaches min_size or after max_time ms, whichever comes
first.
Implements timer-based batching using nsuv::ns_timer, with all timer and
notification logic simplified for clarity and efficiency.
Refactor cctests so the event loop runs on a separate. Also add new
tests covering the new functionality.

PR-URL: #319
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

PR-URL: #326
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

PR-URL: #323
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

PR-URL: #325
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

PR-URL: #324
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

This commit introduces performance optimizations for tracing span
attribute handling by adding two new fast API calls:

1. FastPushSpanDataString - Optimized version of the existing string push method
2. FastPushSpanDataString3 - New method to efficiently handle three string
   values in a single call

Key changes include:
- Avoided JavaScript string concatenation which produces non-flattened V8
  strings that cannot trigger fast API paths
- Implemented direct passing of individual string components to C++ where
  concatenation can happen after the fast API boundary
- Refactored HTTP URL construction in both client and server to leverage
  this optimization
- Improved span context handling by storing trace ID, span ID, and parent
  span ID as separate attributes rather than a single concatenated string

These optimizations significantly improve performance in high load scenarios:
- Up to 3.24% higher throughput in maximum load tests
- Up to 57.75% lower latency at P99.9 under constant high rate (50k req/sec)
- Substantial improvements across all high percentile latencies (P95-P99.999)
- Most dramatic gains observed in tail latencies under sustained heavy load

=== Benchmark Summary ===

Benchmark Type: wrk2 (constant rate)
Old Version: ./nsolid_baseline
New Version: ./nsolid_fast_push_string
Iterations: 50
Connections: 10
Duration: 60s
Rate: 40k req/sec

+------------------+-------------+-------------+------------+-----+
| Metric           | Old Version | New Version | Difference | Sig |
+------------------+-------------+-------------+------------+-----+
| Avg Latency (ms) | 2.58        | 2.34        | N/A        |     |
| P50 Latency (ms) | 1.09        | 1.10        | +0.80%     | *** |
| P90 Latency (ms) | 2.22        | 2.20        | -0.63%     | *** |
| P99 Latency (ms) | 3.09        | 2.99        | -3.31%     | *** |
| Avg Req/Sec      | 39,992.50   | 39,992.53   | +0.00%     |     |
+------------------+-------------+-------------+------------+-----+

=== Benchmark Summary ===

Benchmark Type: wrk2 (constant rate)
Old Version: ./nsolid_baseline
New Version: ./nsolid_fast_push_string
Iterations: 50
Connections: 10
Duration: 60s
Rate: 50k req/sec

+------------------+-------------+-------------+------------+-----+
| Metric           | Old Version | New Version | Difference | Sig |
+------------------+-------------+-------------+------------+-----+
| Avg Latency (ms) | 9.92        | 5.20        | N/A        |     |
| P50 Latency (ms) | 0.95        | 0.94        | -0.54%     |     |
| P90 Latency (ms) | 2.54        | 2.35        | -7.47%     | *** |
| P99 Latency (ms) | 12.00       | 5.58        | -53.49%    | *** |
| Avg Req/Sec      | 49,990.78   | 49,990.72   | -0.00%     |     |
+------------------+-------------+-------------+------------+-----+

=== Benchmark Summary ===

Benchmark Type: wrk (maximum throughput)
Old Version: ./nsolid_baseline
New Version: ./nsolid_fast_push_string
Iterations: 50
Connections: 10
Duration: 60s
Threads: 2

+------------------+-------------+-------------+------------+-----+
| Metric           | Old Version | New Version | Difference | Sig |
+------------------+-------------+-------------+------------+-----+
| Avg Latency (ms) | 0.65        | 0.64        | N/A        |     |
| P50 Latency (ms) | 0.17        | 0.16        | -3.48%     | *** |
| P90 Latency (ms) | 0.33        | 0.32        | -2.30%     | *** |
| P99 Latency (ms) | 0.36        | 0.35        | -3.33%     | *** |
| Avg Req/Sec      | 52,398.20   | 54,094.55   | +3.24%     | *** |
+------------------+-------------+-------------+------------+-----+

PR-URL: #289
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

PR-URL: #284
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

PR-URL: #347
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

No need to install `@grpc/proto-loader` in Makefile's
`test-agents-prereqs` target.

PR-URL: #352
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

On runtime shutdown, when continuous profiling is enabled, it can happen
that we try access `GrpcAgent::cont_prof_queue_` when it has already
being reset, thus crashing the process.

PR-URL: #348
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>