[Bug] PDF missing some svg images but present in html

[david-d-le]

Describe the bug
There are missing some svg images in generated pdf file. All svg images are showing fine in html files and served web page.
However this problem occurs only sometimes (I can't test if it is problem on my machine only or not). Sometimes all images are present and sometimes are some of them (in random order) missing.

To Reproduce
Steps to reproduce the behavior:

1. Download provided sample or Initialize new docfx folder
2. Create some pages containing images
3. run docfx .\docfx.json --serve or even docfx

Expected behavior
Get pdf with correctly generated svg images

Context (please complete the following information):

• OS: Windows 10
• Docfx version: 2.74.1

Additional context
docfx_svg_missing_bug.zip

There is .zip containing sample project with random svg images.

UPDATE
When setting cmd.exe to one thread, it occurs less likely. I don't know if it is coincidence or it has something to do with threads/mutual exclusion??

[yufeih]

We currently print the PDF immediately after script execution, would need to replace it with a more reliable signal that detects renders completes.

Same issue is observed from some of our CI diffs.