Add request start timestamp to request headers to measure performance

[rodolfo3]

Adding timestamp to the request headers allow to use other tools to monitoring queuing time. Tools like New Relic use as X-Queue-Start or X-Request-Start: https://docs.newrelic.com/docs/apm/applications-menu/features/configure-request-queue-reporting

Is something that should be included on planb? Is there a way to do that already?