feat: update type declarations

Author: Pigrabbit

CHANGELOG.md

@@ -18,6 +18,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 
 - Allow Pushgateway to now require job names for compatibility with Gravel Gateway.
+- Allow `histogram.startTime()` to be used with exemplars.
 
 ## [15.0.0] - 2023-10-09
 

index.d.ts

@@ -498,6 +498,19 @@ export class Histogram<T extends string = string> {
 	 */
 	startTimer(labels?: LabelValues<T>): (labels?: LabelValues<T>) => number;
 
+	/**
+	 * Start a timer with exemplar. Calling the returned function will observe the duration in
+	 * seconds in the histogram.
+	 * @param labels Object with label keys and values
+	 * @param exemplarLabels Object with label keys and values for exemplars
+	 * @return Function to invoke when timer should be stopped. The value it
+	 * returns is the timed duration.
+	 */
+	startTimer(
+		labels?: LabelValues<T>,
+		exemplarLabels?: LabelValues<T>,
+	): (labels?: LabelValues<T>, exemplarLabels?: LabelValues<T>) => number;
+
 	/**
 	 * Reset histogram values
 	 */