title: Is there a way to record elapsed time using Prometheus
body: <p>I have a spring-boot application that I have instrumented using <code>Prometheus</code> to collect metric data.  Prometheus has metrics such as <code>Counter</code> that is good for counting the number of times something has happened, <code>Gauge</code> which also keeps count, but can decrease, etc. Is there a metric that would allow me to track the request duration of something? For example, say I want to record the amount of time it takes between when an api call is made, and when the api returns with a response. How would I keep track of the time between when the call is made, and when the api response is received? Then, would it be possible to create a graph where on the <code>Y</code> coordinates, I can list the length of time (in seconds or milliseconds) that the response took; then on the <code>X</code> axis, have the time-stamp (the time when the metric was collected) be shown? </p>