Method set_input

src/langfuse/tracer.cpp:244–249

      trace_start_(std::chrono::system_clock::now()) {}

void Trace::set_input(JsonValue input) {
  if (ended_.load())
    return;
  std::lock_guard<std::mutex> lock(mu_);
  input_ = std::move(input);
}

void Trace::set_output(JsonValue output) {
  if (ended_.load())