Added request duration metric to SD sink
Added request duration metric to SD sink

burmanm/heapster,bluebreezecf/heapster,bluebreezecf/heapster,whuwxl/heapster,Stackdriver/heapster,whuwxl/heapster,krzyzacy/heapster,luxas/heapster,krzyzacy/heapster,burmanm/heapster,luxas/heapster,Stackdriver/heapster,piosz/heapster,piosz/heapster