avoid flushing the extra span

Author: mabdinur

test/system-tests/request_handler.cpp

@@ -257,6 +257,8 @@ void RequestHandler::on_extract_headers(const httplib::Request& req,
 
   res.set_content(response_body.dump(), "application/json");
   http_headers_.emplace(span->parent_id().value(), std::move(*http_headers));
+  // The span below will not be finished and flushed.
+  extract_headers_spans_.emplace(span->parent_id().value(), std::move(*span));
 }
 
 void RequestHandler::on_span_flush(const httplib::Request& /* req */,

test/system-tests/request_handler.h

@@ -38,6 +38,7 @@ class RequestHandler final {
   std::shared_ptr<ManualScheduler> scheduler_;
   std::shared_ptr<DeveloperNoiseLogger> logger_;
   std::unordered_map<uint64_t, datadog::tracing::Span> active_spans_;
+  std::unordered_map<uint64_t, datadog::tracing::Span> extract_headers_spans_;
   std::unordered_map<uint64_t, nlohmann::json::array_t> http_headers_;
 
 #undef VALIDATION_ERROR