pypdfium2/PDFium is not thread-safe - concurrent calls from different
threads can crash or corrupt the process. Added a module-level lock to
serialize all pdfium operations.
PIL image processing and file I/O are done outside the lock since they
are thread-safe, minimizing lock contention.
For maximum parallelism, users can use process-based parallelism
(use_threads=False) where each process has its own pdfium instance.
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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
James R. BarlowandClaude Opus 4.5
ae783b4ae6