From 994f6be535692d0be33bb90de02ba507f9dc98dd Mon Sep 17 00:00:00 2001
From: Andrew Henry <andrew.k.henry@nasa.gov>
Date: Wed, 27 Mar 2019 18:09:13 -0700
Subject: [PATCH] do not return null unsubscribe function (#2335)

---
 src/adapter/runs/LegacyTelemetryProvider.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/adapter/runs/LegacyTelemetryProvider.js b/src/adapter/runs/LegacyTelemetryProvider.js
index 16699a8145..4387d92f87 100644
--- a/src/adapter/runs/LegacyTelemetryProvider.js
+++ b/src/adapter/runs/LegacyTelemetryProvider.js
@@ -137,8 +137,7 @@ define([
         function callbackWrapper(series) {
             callback(createDatum(domainObject, metadata, series, series.getPointCount() - 1));
         }
-
-        return capability.subscribe(callbackWrapper, request);
+        return capability.subscribe(callbackWrapper, request) || function () {};
     };
 
     LegacyTelemetryProvider.prototype.supportsLimits = function (domainObject) {