Add short execution threshold for ExecutionTime plugin

src/jupyter_contrib_nbextensions/nbextensions/execute_time/ExecuteTime.js

@@ -49,6 +49,7 @@ define([
             executed: 'executed in ${duration}, finished ${end_time}',
             queued: 'execution queued ${start_time}',
         },
+        hide_shorter_than_threshold_in_ms: 0,
     };
 
     function patch_CodeCell_get_callbacks () {
@@ -269,6 +270,9 @@ define([
             var exec_time = -start_time.diff(end_time);
             msg = msg.replace('${duration}', humanized_duration(exec_time));
         }
+        if (exec_time < options.hide_shorter_than_threshold_in_ms ) {
+            toggle_timing_display([cell], false);
+        }
         timing_area.text(msg);
         return timing_area;
     }

src/jupyter_contrib_nbextensions/nbextensions/execute_time/ExecuteTime.yaml

@@ -86,3 +86,12 @@ Parameters:
     replacement tokens.
   default: 'execution queued ${start_time}'
   input_type: text
+
+- name: ExecuteTime.hide_shorter_than_threshold_in_ms
+  description: |
+    Hide execution timings that are shorter than this threshold (in ms). Set to 
+    zero to show all timings.
+  default: 0
+  input_type: number
+  step: 1
+  min: 1

src/jupyter_contrib_nbextensions/nbextensions/execute_time/readme.md

@@ -113,6 +113,10 @@ The available options are:
   cells. The template uses an ES2015-like syntax, but replaces only the exact
   strings `${start_time}`, plus (if defined) `${end_time}` and `${duration}`.
   Defaults to `'execution queued ${start_time}'`.
+
+* `ExecuteTime.hide_shorter_than_threshold_in_ms`: Threshold to hide execution 
+  timings that are short. Set this to zero to show all timings.
+  Defaults to `0`.