Race condition when accessing library

Description

We create a temporary file that is a copy of the library when we instantiate a Library instance. This is necessary to avoid a bug in the software that prevents accessing multiple hardware peripherals in a single process. On rare occasions, dlopen will fail with an error along the lines of No Suitable Image found. It seems to best resemble this GRPC issue #5568. The solution seems to be forcing the file to be committed to disk through an atomic write.

Suggested Changes

• Use fsync after os.write when creating a JLock object.
• Flush the outputfile created in Library.load after write, then before closing the temporary file, call fsync on it.
• Add a test to catch this behaviour before the patch, then ensure it's fixed after the patch.

Start by reading the code that creates a JLock object and the Library.load path that writes the temporary library file. Reproduce or add a test for the intermittent dlopen failure, then verify that the file is flushed and synchronized before it is closed and accessed.