From e744957ed5108b1785082cd0b1b51b863c4f195a Mon Sep 17 00:00:00 2001
From: Jason Grout <jgrout6@bloomberg.net>
Date: Thu, 30 Jan 2020 04:20:37 -0800
Subject: [PATCH] Add explanatory comment to classic widget manager

---
 widgetsnbextension/src/manager.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/widgetsnbextension/src/manager.js b/widgetsnbextension/src/manager.js
index 4d1aef0e76..c4a0c7bf74 100644
--- a/widgetsnbextension/src/manager.js
+++ b/widgetsnbextension/src/manager.js
@@ -111,6 +111,9 @@ export class WidgetManager extends baseManager.ManagerBase {
       // for the responses (2).
       return Promise.all(comm_promises)
         .then(function(comms) {
+          // We must do this in batches to make sure we do not
+          // exceed the ZMQ high water mark limiting messages from the kernel. See
+          // https://github.com/voila-dashboards/voila/issues/534 for more details.
           return baseManager.mapBatch(comms, 100, function(comm) {
             var update_promise = new Promise(function(resolve, reject) {
               comm.on_msg(function(msg) {