# File lib/new_relic/agent/commands/thread_profiler_session.rb, line 34
        def start(agent_command)
          NewRelic::Agent.logger.debug("Starting Thread Profiler.")
          profile = @backtrace_service.subscribe(
            NewRelic::Agent::Threading::BacktraceService::ALL_TRANSACTIONS,
            agent_command.arguments
          )

          @started_at = Time.now
          @duration = profile.duration if profile
        end