Extension causes saving files to desktop to be slow

To reproduce:
1. Create a text file (foo.txt) on the desktop and open in gedit.
2. Type a few lines in the file and save it.

Expected: the file saves more or less instantly.

Observed:
- The file takes several seconds to save.
- The following lines appear in the journal:

Apr 26 22:20:40 khaeru-laptop gnome-shell[3205]: JS ERROR: TypeError: fileItem is null
                                                 _updateDesktopIfChanged@/usr/share/gnome-shell/extensions/desktop-icons@csoriano/desktopManager.js:339:17
                                                 _monitorDesktopFolder/<@/usr/share/gnome-shell/extensions/desktop-icons@csoriano/desktopManager.js:299:89

Notes:
- Repeating #1 and #2 with a file that is in another folder (i.e., not on the desktop), the file saves instantly, and the log messages do not appear.
- This might be a duplicate/alternate description of lp#1816205.
- Discovered while trying to diagnose lp#1826219.

$ lsb_release -rd && apt-cache policy gnome-shell-extension-desktop-icons
Description: Ubuntu 19.04
Release: 19.04
gnome-shell-extension-desktop-icons:
  Installed: 19.01.1-1
  Candidate: 19.01.1-1
  Version table:
 *** 19.01.1-1 500
        500 http://us.archive.ubuntu.com/ubuntu disco/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu disco/main i386 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: gnome-shell-extension-desktop-icons 19.01.1-1
ProcVersionSignature: Ubuntu 5.0.0-13.14-generic 5.0.6
Uname: Linux 5.0.0-13-generic x86_64
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Apr 26 22:24:04 2019
EcryptfsInUse: Yes
InstallationDate: Installed on 2017-10-11 (562 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
PackageArchitecture: all
SourcePackage: gnome-shell-extension-desktop-icons
UpgradeStatus: Upgraded to disco on 2019-04-22 (4 days ago)