Merge branch 'master' into zipkin-service-name

Author: mayurkale22

packages/opentelemetry-metrics/src/export/types.ts

@@ -21,8 +21,12 @@ import { Resource } from '@opentelemetry/resources';
 /** The kind of metric. */
 export enum MetricKind {
   COUNTER,
+  UP_DOWN_COUNTER,
   VALUE_RECORDER,
-  OBSERVER,
+  OBSERVER, // @TODO remove later #1146
+  SUM_OBSERVER,
+  UP_DOWN_SUM_OBSERVER,
+  VALUE_OBSERVER,
 }
 
 /** Sum returns an aggregated sum. */